Last data update: Apr 18, 2025. (Total: 49119 publications since 2009)
Records 1-30 (of 47 Records) |
Query Trace: Cantey P[original query] |
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Changes in anti-OV-16 IgG4 responses to onchocerciasis after elimination of transmission in the central endemic zone of Guatemala
Cama VA , Mendizabal-Cabrera R , de Leon O , White M , McDonald C , Thiele E , Ogawa GM , Morales Z , Prince-Guerra J , Cantey P , Rizzo N . Am J Trop Med Hyg 2024 Current WHO guidelines for onchocerciasis elimination provide requirements for stopping mass drug administration of ivermectin and the verification of elimination of transmission. These guidelines also recommend post-elimination surveillance (PES) based on entomological surveys. Serological markers in humans could complement entomological PES once the longevity of anti-OV-16 antibody responses is better understood. In 2014-2015 we evaluated ELISA anti-OV-16 IgG4 antibody persistence among previously seropositive people from the central endemic zone of Guatemala. The country stopped all onchocerciasis program interventions in 2012 and was verified by WHO as having eliminated transmission of onchocerciasis in 2016. A total of 246 participants with prior OV-16 ELISA results from 2003, 2006, 2007, or 2009 were enrolled in a follow-up study. Of these, 77 people were previously OV-16 seropositive and 169 were previously seronegative. By 2014 and 2015, 56 (72.7%) previously seropositive individuals had sero-reverted, whereas all previous negatives remained seronegative. The progression of antibody responses over time was estimated using a mixed-effects linear regression model, using data from seropositive participants who had sero-reverted. The temporal variation showed a mean activity unit decay of 0.20 per year (95% credible interval [CrI]: 0.17, 0.23), corresponding to an estimated antibody response half-life of 3.3 years (95% CrI: 2.7, 4.1). These findings indicate that the majority of seropositive people will sero-revert over time. |
Neuroinvasive Onchocerca lupi infection in a ten-year-old girl
Bowers Wu D , Ko B , Lopez Hernandez G , Botros J , Spader H , Sapp S , Qvarnstrom Y , Paddock CD , Cantey PT , Dehority W . Case Rep Infect Dis 2022 2022 9773058 The nematode Onchocerca lupi is an emerging human pathogen. Though its life cycle is not well studied, it likely infects humans after a bite from a black fly vector, which in turn acquires infective microfilariae from an infected canid. These microfilariae mature into an infective larval stage within the fly. Among six reported cases in the United States, five involved children, and all occurred in the southwest. In this report, we present a case of O. lupi infection with cervical spine invasion in a healthy 10-year-old girl. She presented with five months of neurological symptoms from a rural and medically underserved area, highlighting a need for clinical vigilance in such settings for this emerging infectious threat in the American southwest. |
A bicyclist's tale
Min Z , Alvarez G , Rao S , Khoury F , Cheema T , Bhanot N , Bishop HS , Qvarnstrom Y , Sapp SGH , Cantey PT . Clin Infect Dis 2022 75 (4) 729-731 In August, a 55-year-old man presented with fever, progressive lethargy, body aches, joint pains, and intermittent confusion that lasted for 10 days. Past medical history included alcohol use and splenectomy. The patient was a resident of western Pennsylvania, lived in the countryside, and enjoyed bicycling. He did not recall being bitten by a tick or receiving a blood transfusion. He had not traveled out of the state or abroad prior to symptom onset. |
Onchocerciasis: Target product profiles of in vitro diagnostics to support onchocerciasis elimination mapping and mass drug administration stopping decisions
Biamonte MA , Cantey PT , Coulibaly YI , Gass KM , Hamill LC , Hanna C , Lammie PJ , Kamgno J , Nutman TB , Oguttu DW , Sankara DP , Stolk WA , Unnasch TR . PLoS Negl Trop Dis 2022 16 (8) e0010682 In June 2021, the World Health Organization (WHO), recognizing the need for new diagnostics to support the control and elimination of onchocerciasis, published the target product profiles (TPPs) of new tests that would support the two most immediate needs: (a) mapping onchocerciasis in areas of low prevalence and (b) deciding when to stop mass drug administration programs. In both instances, the test should ideally detect an antigen specific for live, adult O. volvulus female worms. The preferred format is a field-deployable rapid test. For mapping, the test needs to be ≥ 60% sensitive and ≥ 99.8% specific, while to support stopping decisions, the test must be ≥ 89% sensitive and ≥ 99.8% specific. The requirement for extremely high specificity is dictated by the need to detect with sufficient statistical confidence the low seroprevalence threshold set by WHO. Surveys designed to detect a 1-2% prevalence of a given biomarker, as is the case here, cannot tolerate more than 0.2% of false-positives. Otherwise, the background noise would drown out the signal. It is recognized that reaching and demonstrating such a stringent specificity criterion will be challenging, but test developers can expect to be assisted by national governments and implementing partners for adequately powered field validation. |
Neglected parasitic infections: What family physicians need to know-a CDC update
Cantey PT , Montgomery SP , Straily A . Am Fam Physician 2021 104 (3) 277-287 Chagas disease, cysticercosis, and toxoplasmosis affect millions of people in the United States and are considered neglected parasitic diseases. Few resources are devoted to their surveillance, prevention, and treatment. Chagas disease, transmitted by kissing bugs, primarily affects people who have lived in Mexico, Central America, and South America, and it can cause heart disease and death if not treated. Chagas disease is diagnosed by detecting the parasite in blood or by serology, depending on the phase of disease. Antiparasitic treatment is indicated for most patients with acute disease. Treatment for chronic disease is recommended for people younger than 18 years and generally recommended for adults younger than 50 years. Treatment decisions should be individualized for all other patients. Cysticercosis can manifest in muscles, the eyes, and most critically in the brain (neurocysticercosis). Neurocysticercosis accounts for 2.1% of all emergency department visits for seizures in the United States. Diagnosing neurocysticercosis involves serology and neuroimaging. Treatment includes symptom control and antiparasitic therapy. Toxoplasmosis is estimated to affect 11% of people older than six years in the United States. It can be acquired by ingesting food or water that has been contaminated by cat feces; it can also be acquired by eating undercooked, contaminated meat. Toxoplasma infection is usually asymptomatic; however, people who are immunosuppressed can develop more severe neurologic symptoms. Congenital infection can result in miscarriage or adverse fetal effects. Diagnosis is made with serologic testing, polymerase chain reaction testing, or parasite detection in tissue or fluid specimens. Treatment is recommended for people who are immunosuppressed, pregnant patients with recently acquired infection, and people who are immunocompetent with visceral disease or severe symptoms. |
A framework for scabies control
Engelman D , Marks M , Steer AC , Beshah A , Biswas G , Chosidow O , Coffeng LE , Lardizabal Dofitas B , Enbiale W , Fallah M , Gasimov E , Hopkins A , Jacobson J , Kaldor JM , Ly F , Mackenzie CD , McVernon J , Parnaby M , Rainima-Qaniuci M , Sokana O , Sankara D , Yotsu R , Yajima A , Cantey PT . PLoS Negl Trop Dis 2021 15 (9) e0009661 Scabies is a neglected tropical disease (NTD) that causes a significant health burden, particularly in disadvantaged communities and where there is overcrowding. There is emerging evidence that ivermectin-based mass drug administration (MDA) can reduce the prevalence of scabies in some settings, but evidence remains limited, and there are no formal guidelines to inform control efforts. An informal World Health Organization (WHO) consultation was organized to find agreement on strategies for global control. The consultation resulted in a framework for scabies control and recommendations for mapping of disease burden, delivery of interventions, and establishing monitoring and evaluation. Key operational research priorities were identified. This framework will allow countries to set control targets for scabies as part of national NTD strategic plans and develop control strategies using MDA for high-prevalence regions and outbreak situations. As further evidence and experience are collected and strategies are refined over time, formal guidelines can be developed. The control of scabies and the reduction of the health burden of scabies and associated conditions will be vital to achieving the targets set in WHO Roadmap for NTDs for 2021 to 2030 and the Sustainable Development Goals. |
Scaling-down mass ivermectin treatment for onchocerciasis elimination: modelling the impact of the geographical unit for decision making
Stolk WA , Blok DJ , Hamley JID , Cantey PT , de Vlas SJ , Walker M , Basáñez MG . Clin Infect Dis 2021 72 S165-S171 BACKGROUND: Due to spatial heterogeneity in onchocerciasis transmission, the duration of ivermectin mass drug administration (MDA) required for eliminating onchocerciasis will vary within endemic areas and the occurrence of transmission 'hotspots' is inevitable. The geographical scale at which stop-MDA decisions are made will be a key driver in how rapidly national programmes can scale down active intervention upon achieving the epidemiological targets for elimination. METHODS: We use two onchocerciasis models (EPIONCHO-IBM and ONCHOSIM) to predict the likelihood of achieving elimination by 2030 in Africa, accounting for variation in pre-intervention endemicity levels and histories of ivermectin treatment. We explore how decision-making at contrasting geographical scales (community vs. larger scale 'project') changes projections on populations still requiring MDA or transitioning to post-treatment surveillance. RESULTS: The total population considered grows from 118 million people in 2020 to 136 million in 2030. If stop-MDA decisions are made at project level, the number of people requiring treatment declines from 69-118 million in 2020 to 59-118 million in 2030. If stop-MDA decisions are made at community level, the numbers decline from 23-81 million in 2020 to 15-63 million in 2030. The lower estimates in these predictions intervals are based on ONCHOSIM, the upper limits on EPIONCHO-IBM. DISCUSSION/CONCLUSIONS: The geographical scale at which stop-MDA decisions are made strongly determines how rapidly national onchocerciasis programmes can scale down MDA programmes. Stopping in portions of project areas or transmission zones would free up human and economic resources. |
Pediatric research priorities in healthcare-associated infections and antimicrobial stewardship
Coffin SE , Abanyie F , Bryant K , Cantey J , Fiore A , Fritz S , Guzman-Cottrill J , Hersh AL , Huskins WC , Kociolek LK , Kronman M , Lautenbach E , Lee G , Linam M , Logan LK , Milstone A , Newland J , Nyquist AC , Palazzi DL , Patel S , Puopolo K , Reddy SC , Saiman L , Sandora T , Shane AL , Smith M , Tamma PD , Zaoutis T , Zerr D , Gerber JS . Infect Control Hosp Epidemiol 2020 42 (5) 1-4 OBJECTIVE: To develop a pediatric research agenda focused on pediatric healthcare-associated infections and antimicrobial stewardship topics that will yield the highest impact on child health. PARTICIPANTS: The study included 26 geographically diverse adult and pediatric infectious diseases clinicians with expertise in healthcare-associated infection prevention and/or antimicrobial stewardship (topic identification and ranking of priorities), as well as members of the Division of Healthcare Quality and Promotion at the Centers for Disease Control and Prevention (topic identification). METHODS: Using a modified Delphi approach, expert recommendations were generated through an iterative process for identifying pediatric research priorities in healthcare associated infection prevention and antimicrobial stewardship. The multistep, 7-month process included a literature review, interactive teleconferences, web-based surveys, and 2 in-person meetings. RESULTS: A final list of 12 high-priority research topics were generated in the 2 domains. High-priority healthcare-associated infection topics included judicious testing for Clostridioides difficile infection, chlorhexidine (CHG) bathing, measuring and preventing hospital-onset bloodstream infection rates, surgical site infection prevention, surveillance and prevention of multidrug resistant gram-negative rod infections. Antimicrobial stewardship topics included β-lactam allergy de-labeling, judicious use of perioperative antibiotics, intravenous to oral conversion of antimicrobial therapy, developing a patient-level "harm index" for antibiotic exposure, and benchmarking and or peer comparison of antibiotic use for common inpatient conditions. CONCLUSIONS: We identified 6 healthcare-associated infection topics and 6 antimicrobial stewardship topics as potentially high-impact targets for pediatric research. |
COVID-19 in Americans aboard the Diamond Princess cruise ship.
Plucinski MM , Wallace M , Uehara A , Kurbatova EV , Tobolowsky FA , Schneider ZD , Ishizumi A , Bozio CH , Kobayashi M , Toda M , Stewart A , Wagner RL , Moriarty LF , Murray R , Queen K , Tao Y , Paden C , Mauldin MR , Zhang J , Li Y , Elkins CA , Lu X , Herzig CTA , Novak R , Bower W , Medley AM , Acosta AM , Knust B , Cantey PT , Pesik NT , Halsey ES , Cetron MS , Tong S , Marston BJ , Friedman CR . Clin Infect Dis 2020 72 (10) e448-e457 ![]() ![]() BACKGROUND: The Diamond Princess cruise ship was the site of a large outbreak of coronavirus disease 2019 (COVID-19). Of 437 Americans and their travel companions on the ship, 114 (26%) tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: We interviewed 229 American passengers and crew after disembarkation following a ship-based quarantine to identify risk factors for infection and characterize transmission onboard the ship. RESULTS: The attack rate for passengers in single-person cabins or without infected cabinmates was 18% (58/329), compared with 63% (27/43) for those sharing a cabin with an asymptomatic infected cabinmate, and 81% (25/31) for those with a symptomatic infected cabinmate. Whole genome sequences from specimens from passengers who shared cabins clustered together. Of 66 SARS-CoV-2-positive American travelers with complete symptom information, 14 (21%) were asymptomatic while on the ship. Among SARS-CoV-2-positive Americans, 10 (9%) required intensive care, of whom 7 were ≥70 years. CONCLUSION: Our findings highlight the high risk of SARS-CoV-2 transmission on cruise ships. High rates of SARS-CoV-2 positivity in cabinmates of individuals with asymptomatic infections suggest that triage by symptom status in shared quarters is insufficient to halt transmission. A high rate of intensive care unit admission among older individuals complicates the prospect of future cruise travel during the pandemic, given typical cruise passenger demographics. The magnitude and severe outcomes of this outbreak were major factors contributing to the Centers for Disease Control and Prevention's decision to halt cruise ship travel in U.S. waters in March 2020. |
Malaria and Parasitic Neglected Tropical Diseases: Potential Syndemics with COVID-19?
Gutman JR , Lucchi NW , Cantey PT , Steinhardt LC , Samuels AM , Kamb ML , Kapella BK , McElroy PD , Udhayakumar V , Lindblade KA . Am J Trop Med Hyg 2020 103 (2) 572-577 The COVID-19 pandemic, caused by SARS-CoV-2, have surpassed 5 million cases globally. Current models suggest that low- and middle-income countries (LMICs) will have a similar incidence but substantially lower mortality rate than high-income countries. However, malaria and neglected tropical diseases (NTDs) are prevalent in LMICs, and coinfections are likely. Both malaria and parasitic NTDs can alter immunologic responses to other infectious agents. Malaria can induce a cytokine storm and pro-coagulant state similar to that seen in severe COVID-19. Consequently, coinfections with malaria parasites and SARS-CoV-2 could result in substantially worse outcomes than mono-infections with either pathogen, and could shift the age pattern of severe COVID-19 to younger age-groups. Enhancing surveillance platforms could provide signals that indicate whether malaria, NTDs, and COVID-19 are syndemics (synergistic epidemics). Based on the prevalence of malaria and NTDs in specific localities, efforts to characterize COVID-19 in LMICs could be expanded by adding testing for malaria and NTDs. Such additional testing would allow the determination of the rates of coinfection and comparison of severity of outcomes by infection status, greatly improving the understanding of the epidemiology of COVID-19 in LMICs and potentially helping to mitigate its impact. |
Public Health Responses to COVID-19 Outbreaks on Cruise Ships - Worldwide, February-March 2020.
Moriarty LF , Plucinski MM , Marston BJ , Kurbatova EV , Knust B , Murray EL , Pesik N , Rose D , Fitter D , Kobayashi M , Toda M , Canty PT , Scheuer T , Halsey ES , Cohen NJ , Stockman L , Wadford DA , Medley AM , Green G , Regan JJ , Tardivel K , White S , Brown C , Morales C , Yen C , Wittry B , Freeland A , Naramore S , Novak RT , Daigle D , Weinberg M , Acosta A , Herzig C , Kapella BK , Jacobson KR , Lamba K , Ishizumi A , Sarisky J , Svendsen E , Blocher T , Wu C , Charles J , Wagner R , Stewart A , Mead PS , Kurylo E , Campbell S , Murray R , Weidle P , Cetron M , Friedman CR . MMWR Morb Mortal Wkly Rep 2020 69 (12) 347-352 ![]() ![]() An estimated 30 million passengers are transported on 272 cruise ships worldwide each year* (1). Cruise ships bring diverse populations into proximity for many days, facilitating transmission of respiratory illness (2). SARS-CoV-2, the virus that causes coronavirus disease (COVID-19) was first identified in Wuhan, China, in December 2019 and has since spread worldwide to at least 187 countries and territories. Widespread COVID-19 transmission on cruise ships has been reported as well (3). Passengers on certain cruise ship voyages might be aged >/=65 years, which places them at greater risk for severe consequences of SARS-CoV-2 infection (4). During February-March 2020, COVID-19 outbreaks associated with three cruise ship voyages have caused more than 800 laboratory-confirmed cases among passengers and crew, including 10 deaths. Transmission occurred across multiple voyages of several ships. This report describes public health responses to COVID-19 outbreaks on these ships. COVID-19 on cruise ships poses a risk for rapid spread of disease, causing outbreaks in a vulnerable population, and aggressive efforts are required to contain spread. All persons should defer all cruise travel worldwide during the COVID-19 pandemic. |
The public health control of scabies: priorities for research and action
Engelman D , Cantey PT , Marks M , Solomon AW , Chang AY , Chosidow O , Enbiale W , Engels D , Hay RJ , Hendrickx D , Hotez PJ , Kaldor JM , Kama M , Mackenzie CD , McCarthy JS , Martin DL , Mengistu B , Maurer T , Negussu N , Romani L , Sokana O , Whitfeld MJ , Fuller LC , Steer AC . Lancet 2019 394 (10192) 81-92 Scabies is a parasitic disease of the skin that disproportionately affects disadvantaged populations. The disease causes considerable morbidity and leads to severe bacterial infection and immune-mediated disease. Scientific advances from the past 5 years suggest that scabies is amenable to population-level control, particularly through mass drug administration. In recognition of these issues, WHO added scabies to the list of neglected tropical diseases in 2017. To develop a global control programme, key operational research questions must now be addressed. Standardised approaches to diagnosis and methods for mapping are required to further understand the burden of disease. The safety of treatments for young children, including with ivermectin and moxidectin, should be investigated. Studies are needed to inform optimum implementation of mass treatment, including the threshold for intervention, target, dosing, and frequency. Frameworks for surveillance, monitoring, and evaluation of control strategies are also necessary. |
Onchocerciasis associated epilepsy - A question of causality
Cantey PT , Sejvar J . Int J Infect Dis 2019 79 185-186 Recently there have been many studies reporting the detection of a high prevalence of epilepsy in areas that are hyperendemic for onchocerciasis. In many of these studies, including the manuscript by Mukendi and colleagues in this issue of International Journal of Infectious Diseases a positive association between past or current infection with onchocerciasis has been found. However, not all studies have found such an association. An earlier meta-analysis did not find a statistically significant association (Druet-Cabanac et al., 2004). More recent meta-analyses have generally affirmed the association between onchocerciasis and epilepsy (Kaiser et al., 2013, Pion et al., 2009), but only after pooling data from heterogeneous studies that have used varying methodologies to diagnosis both exposure and outcome. In some cases, including this current study and one of the previously published meta-analyses (Kaiser et al., 2013), the association weakens or disappears when controlling for potential confounders which suggests that confounders may explain part or all of the association. One recent retrospective case-control study found a dose response between a single measurement of microfilarial density in the skin and the development of epilepsy over a period of follow-up of up to 26 years (Chesnais et al., 2018). Unfortunately, the numbers were small, no information about potential confounders was available, and there was potential for misclassification of the outcome as the diagnosis of epilepsy was not confirmed by a neurologist. Although retrospective case-control studies cannot establish causality and no pathophysiologic mechanism has been described which explains how onchocerciasis causes epilepsy, the finding of a potential dose response will keep the debate about causality alive. |
Evaluation of an OV-16 IgG4 enzyme-linked immunosorbent assay in humans and its application to determine the dynamics of antibody responses in a non-human primate model of Onchocerca volvulus infection
Cama VA , McDonald C , Arcury-Quandt A , Eberhard M , Jenks MH , Smith J , Feleke SM , Abanyie F , Thomson L , Wiegand RE , Cantey PT . Am J Trop Med Hyg 2018 99 (4) 1041-1048 Onchocerciasis is a neglected parasitic disease targeted for elimination. Current World Health Organization guidelines for elimination include monitoring antibody responses to the recombinant Onchocerca volvulus antigen OV-16 in children to demonstrate the absence of transmission. We report the performance characteristics of a modified OV-16 enzyme-linked immunosorbent assay (ELISA) and describe anti-OV-16 responses in serum samples from laboratory-inoculated nonhuman primates (NHPs) in relation to microfilariae (mf) in skin snip biopsies. This OV-16 IgG4 ELISA had sensitivity and specificity of 88.2% and 99.7%, respectively, as determined by receiver operator characteristic analysis using a serum panel of 110 positive and 287 negative samples from people infected with other filariae or other parasitic infections. Anti-OV-16 responses in inoculated NHP (N = 9) were evaluated at quarterly intervals for IgM and the four IgG subclasses. Enzyme-linked immunosorbent assay results showed a well-defined IgG4 reactivity pattern and moderate IgG1 antibody responses. Meanwhile, the reactivity by IgG2, IgG3, or IgM did not show a clear pattern. Temporal evolution of IgG4 reactivity was evaluated through monthly testing, showing that NHPs developed anti-OV-16 IgG4 on average at 15 months postinoculation (range: 10-18 months). The average time to detectable mf was also 15 months (range: 11-25). The OV-16 ELISA used in this study was robust and allowed the detection of IgG4 responses, which were observed only among animals with detectable mf (N = 5), four of which showed declines in antibody responses once mf cleared. These findings also confirmed that the most informative antibody subclass responses to OV-16 are IgG4. |
Comparison of PCR methods for Onchocerca volvulus detection in skin snip biopsies from the Tshopo Province, Democratic Republic of the Congo
Prince-Guerra J , Cama V , Wilson N , Thiele EA , Likwela J , Gyamba NN , Muzinga Wa Muzinga J , Ayebazibwe N , Ndjakani YD , Pitchouna NA , Ngoyi DM , Tshefu AK , Ogawa G , Cantey PT . Am J Trop Med Hyg 2018 98 (5) 1427-1434 Defining the optimal diagnostic tools for evaluating onchocerciasis elimination efforts in areas co-endemic for other filarial nematodes is imperative. This study compared three published PCR methods: the Onchocerca volvulus-specific qPCR-O150, the pan-filarial qPCR melt curve analysis (MCA), and the O150-PCR ELISA currently used for vector surveillance in skin snip biopsies (skin snips) collected from the Democratic Republic of the Congo. The pan-filarial qPCR-MCA was compared with species-specific qPCRs for Loa loa and Mansonella perstans. Among the 471 skin snips, 47.5%, 43.5%, and 27% were O. volvulus positive by qPCR-O150, qPCR-MCA, and O150-PCR ELISA, respectively. Using qPCR-O150 as the comparator, the sensitivity and specificity of qPCR-MCA were 89.3% and 98%, respectively, whereas for O150-PCR ELISA, they were 56.7% and 100%, respectively. Although qPCR-MCA identified the presence of L. loa and Mansonella spp. in skin snips, species-specific qPCRs had greater sensitivity and were needed to identify M. perstans. Most of the qPCR-MCA misclassifications occurred in mixed infections. The reduced sensitivity of O150-PCR ELISA was associated with lower microfilaria burden and with lower amounts of O. volvulus DNA. Although qPCR-MCA identified most of the O. volvulus-positive skin snips, it is not sufficiently robust to be used for stop-mass drug administration (MDA) evaluations in areas co-endemic for other filariae. Because O150-PCR ELISA missed 43.3% of qPCR-O150-positive skin snips, the qPCR-O150 assay is more appropriate for evaluating skin snips of OV-16 + children in stop-MDA assessments. Although improving the sensitivity of the O150-PCR ELISA as an alternative to qPCR might be possible, qPCR-O150 offers distinct advantages aside from increased sensitivity. |
Diagnostics for onchocerciasis in the era of elimination
Unnasch TR , Golden A , Cama V , Cantey PT . Int Health 2018 10 i20-i26 In the past few years, efforts to eliminate onchocerciasis from Africa have intensified. These efforts are primarily based on the mass distribution of the anti-helminthic drug Mectizan (ivermectin). This program has led to the development of new guidelines by the World Health Organization for the verification that transmission has been suppressed and eventually eliminated. The requirements of diagnostic tools for this purpose differ in many ways from tests used to diagnose infection in individuals. In this review, we summarize the progress that has been made to identify diagnostics that meet the specialized requirements needed to verify onchocerciasis elimination, discuss why these tests were selected and summarize the needs that still exist to complete the arsenal of diagnostic tools that will be useful as the goal of elimination is achieved. |
Transitioning from river blindness control to elimination: steps toward stopping treatment
Cantey PT , Roy SL , Boakye D , Mwingira U , Ottesen EA , Hopkins AD , Sodahlon YK . Int Health 2018 10 i7-i13 The transition from onchocerciasis control to elimination requires country programmes to rethink their approach to a variety of activities as they move from addressing morbidity to addressing transmission of the parasite. Although the 2016 WHO guidelines provide extensive recommendations, it was beyond the scope of the document to provide guidance on all aspects of the transition. This paper will discuss some of the important issues that programmes are grappling with as they transition to elimination and provide some potential approaches that programmes can use to address them. Although there are some data to support some aspects of the suggested approaches, operational research will be needed to generate data to support these approaches further and to determine how programmes could best tailor them to their own unique epidemiological challenges. Good communication between the national programmes and the broader global programme will facilitate the clear articulation of programmatic challenges and the development of the evidence to support programme decision-making. |
2017 Infectious Diseases Society of America clinical practice guidelines for the diagnosis and management of infectious diarrhea
Shane AL , Mody RK , Crump JA , Tarr PI , Steiner TS , Kotloff K , Langley JM , Wanke C , Warren CA , Cheng AC , Cantey J , Pickering LK . Clin Infect Dis 2017 65 (12) e45-e80 These guidelines are intended for use by healthcare professionals who care for children and adults with suspected or confirmed infectious diarrhea. They are not intended to replace physician judgement regarding specific patients or clinical or public health situations. This document does not provide detailed recommendations on infection prevention and control aspects related to infectious diarrhea. |
Characterizing reactivity to Onchocerca volvulus antigens in multiplex bead assays
Feeser KR , Cama V , Priest JW , Thiele EA , Wiegand RE , Lakwo T , Feleke SM , Cantey PT . Am J Trop Med Hyg 2017 97 (3) 666-672 Multiplex bead assays (MBAs) may provide a powerful integrated tool for monitoring, evaluation, and post-elimination surveillance of onchocerciasis and co-endemic diseases; however, the specificity and sensitivity of Onchocerca volvulus antigens have not been characterized within this context. An MBA was developed to evaluate three antigens (OV-16, OV-17, and OV-33) for onchocerciasis. Receiver operating characteristics (ROC) analyses were used to characterize antigen performance using a panel of 610 specimens: 109 O. volvulus-positive specimens, 426 non-onchocerciasis controls with filarial and other confirmed parasitic infection, and 75 sera from patients with no other parasitic infection. The IgG and IgG4 assays for OV-16 demonstrated sensitivities of 95.4% and 96.3%, and specificities of 99.4% and 99.8%, respectively. The OV-17 IgG and IgG4 assays had sensitivities of 86.2% and 76.1% and specificities of 79.2% and 82.8%. For OV-33, the IgG and IgG4 assays had sensitivities of 90.8% and 96.3%, and specificities of 96.8% and 98.6%. The OV-16 IgG4-based MBA had the best assay characteristics, followed by OV-33 IgG4. The OV-16 IgG4 assay would be useful for monitoring and evaluation using the MBA platform. Further evaluations are needed to review the potential use of OV-33 as a confirmatory test in the context of program evaluations. |
Evaluation of onchocerciasis transmission in Tanzania: Preliminary rapid field results in the Tukuyu Focus, 2015
Paulin HN , Nshala A , Kalinga A , Mwingira U , Wiegand R , Cama V , Cantey PT . Am J Trop Med Hyg 2017 97 (3) 673-676 To compare diagnostic tests for onchocerciasis in a setting that has suppressed transmission, a randomized, age-stratified study was implemented in an area in Tanzania that had received 15 rounds of annual mass drug administration (MDA) with ivermectin. Study participants (N = 948) from 11 villages underwent a questionnaire, skin examination, skin snips, and blood draw. The burden of symptomatic disease was low. Ov-16 antibody rapid diagnostic test (RDT) results were positive in 38 (5.5%) participants, with 1 (0.5%), 1 (0.4%), and 2 (0.8%) in children aged 0-5, 6-10, and 11-15 years, respectively. Despite significant impact of MDA on transmission, the area would have failed to meet World Health Organization serologic criteria for stopping MDA if a full evaluation had been conducted. The specificity of the RDT, which is 97-98%, may result in the identification of a number of false positives that would exceed the current stop MDA threshold. |
Survey of obstetrician-gynecologists in the United States about taeniasis and cysticercosis
Hall RL , Anderson B , Schulkin J , Cantey PT , Montgomery SP , Jones JL . Am J Trop Med Hyg 2017 96 (1) 233-242 An estimated 50 million persons worldwide are infected with cysticerci, the larval forms of the Taenia solium tapeworm. Neurocysticercosis can cause seizures, epilepsy, and hydrocephalus, and fatal cases have been reported in the United States in immigrants and in travelers returning from endemic countries. Pregnant women with symptomatic neurocysticercosis present treatment challenges, whereas those with the adult tapeworm infection (i.e., taeniasis) can put their infants and other family members, as well as obstetrician-gynecologists and their staff, at risk for cysticercosis. A questionnaire developed by the American College of Obstetricians and Gynecologists was sent to a representative sample of 1,000 physicians to assess their awareness of T. solium infection and the potential for it to be encountered in an obstetrics and gynecology setting. In total, 31.4% of respondents correctly answered that taeniasis is caused by eating undercooked pork containing T. solium cysts (95% confidence interval [CI] = 26.6-36.5). While only 14.5% (95% CI = 11.0-18.6) of respondents correctly answered that cysticercosis is acquired by ingesting tapeworm eggs shed in human stools, twice that number (30.3%; 95% CI = 25.5-35.3) correctly answered that a mother with taeniasis can cause cysticercosis in her infant. Practicing in a state in which cysticercosis was reportable at the time of the survey was not significantly associated with answering any of the 12 knowledge questions correctly. Overall, knowledge of T. solium infection among U.S. obstetricians-gynecologists is limited. This may result in missed opportunities to diagnose and treat pregnant women with taeniasis, which may put family members and obstetrics clinical staff at risk for cysticercosis. |
Evaluation of lymphatic filariasis and onchocerciasis in three Senegalese districts treated for onchocerciasis with ivermectin
Wilson NO , Badara Ly A , Cama VA , Cantey PT , Cohn D , Diawara L , Direny A , Fall M , Feeser KR , Fox LM , Kabore A , Seck AF , Sy N , Ndiaye D , Dubray C . PLoS Negl Trop Dis 2016 10 (12) e0005198 In Africa, onchocerciasis and lymphatic filariasis (LF) are co-endemic in many areas. Current efforts to eliminate both diseases are through ivermectin-based mass drug administration (MDA). Years of ivermectin distribution for onchocerciasis may have interrupted LF transmission in certain areas. The Kedougou region, Senegal, is co-endemic for LF and onchocerciasis. Though MDA for onchocerciasis started in 1988, in 2014 albendazole had not yet been added for LF. The objective of this study was to assess in an integrated manner the LF and onchocerciasis status in the three districts of the Kedougou region after ≥10 years of ivermectin-based MDA. The study employed an African Programme for Onchocerciasis Control (APOC) onchocerciasis-related methodology. In the three districts, 14 villages close to three rivers that have Simulium damnosum breeding sites were surveyed. Convenience sampling of residents ≥5 years old was performed. Assessment for LF antigenemia by immunochromatographic testing (ICT) was added to skin snip microscopy for onchocerciasis. Participants were also tested for antibodies against Wb123 (LF) and Ov16 (onchocerciasis) antigens. In two districts, no participants were ICT or skin snip positive. In the third district, 3.5% were ICT positive and 0.7% were skin snip positive. In all the three districts, Wb123 prevalence was 0.6%. Overall, Ov16 prevalence was 6.9%. Ov16 prevalence among children 5-9 years old in the study was 2.5%. LF antigenemia prevalence was still above treatment threshold in one district despite ≥10 years of ivermectin-based MDA. The presence of Ov16 positive children suggested recent transmission of Onchocerca volvulus. This study showed the feasibility of integrated evaluation of onchocerciasis and LF but development of integrated robust methods for assessing transmission of both LF and onchocerciasis are needed to determine where MDA can be stopped safely in co-endemic areas. |
Letter to the Editor: Onchocerca lupi infection
Cantey PT , Eberhard M , Weeks J , Swoboda S , Ostovar GA . J Neurosurg Pediatr 2016 17 (1) 118-9 It was with great interest that we | read the paper by Chen and colleagues2 | (Chen T, Moon K, | deMello DE, et al: Case report of an epidural cervical Onchocerca lupi infection in a 13-year-old boy. J Neurosurg | Pediatr 16:217–221, August 2015). Our understanding of | this complex emerging pathogen is evolving, and this case | report adds to that understanding. However, we are concerned by several points made by the authors that could be | misleading or wrong. The first statement of concern is that | O. lupi is the only species other than O. volvulus, the parasite that causes river blindness, that has been reported to | infect humans. This is incorrect, as several other zoonotic | species have been reported to infect humans.5 | It is, however, the only zoonotic onchocercal infection reported to | have involved the spine. This report increases the number | of patients with spinal involvement to three.4,5 | Later in the paper the authors discuss options for medical | therapy for the parasite. They state that doxycycline therapy was not effective in their patient because re-exploration | and debulking of the original mass was required when it | became inflamed 10 weeks after the initial surgery. They | mention the case of the 22-month-old girl who was treated | with doxycycline followed by ivermectin. First, to the best | of our knowledge the girl was not treated with doxycycline.5 | Second, recommendations for medical therapy for | O. lupi are based primarily on what is known about the | treatment of O. volvulus. Based on what is known, it would | be premature to make any statement on the efficacy of either therapy. Ivermectin kills the microfilariae (juvenile | form) of O. volvulus, preventing the symptomatic manifestations of river blindness and reducing the probability that | black flies will become infected and maintain the cycle of | transmission.1 | There are limited data that treating an individual with ivermectin 4 times a year will accelerate the | sterilization and death of the adult female parasites; however, this effect takes up to 5 years or more.3 | Doxycycline | is known to kill the adult form of O. volvulus because of | its effects on the Wolbachia endosymbiont, which is required for reproduction and the long-term survival of the | parasite.6 | However, this effect takes 21–27 months.6,7 The | patient discussed by Chen and colleagues has not been on | ivermectin therapy long enough for it to have resulted in | the death of adult parasites, nor has enough time elapsed | to determine the efficacy of doxycycline. Because we do | not currently have a noninvasive test, medical therapy is | primarily directed at the prevention of symptoms due to | parasites not found in the resected biopsy. | Although Chen and colleagues state that they believe | their patient may have been reinfected, there are other potential explanations. One possible explanation for what occurred could be that the biopsy killed the adult parasite(s) | in the nodule but did not result in complete resection of it | (them). The expected inflammatory response to the dead | parasite(s) may have been delayed by the use of dexamethasone, so the inflammation surrounding the dead | parasite(s) did not become symptomatic until 10 weeks | after the initial surgery. Importantly, the case report illustrates that there may be a role for corticosteroids in patients with spinal nodules due to O. lupi, although more | information will be needed to determine if their use can | reduce the need for additional surgical interventions |
Notes from the field: Splenomegaly of unknown etiology in Congolese refugees applying for resettlement to the United States - Uganda, 2015
Goers M , Ope MO , Samuels A , Gitu N , Akandwanaho S , Nabwami G , Nyoka R , Cetron MS , Dalal W , Conroy AL , Cantey P , John C , Naoum M , Weinberg M , Marano N , Stauffer W . MMWR Morb Mortal Wkly Rep 2016 65 (35) 943-944 Approximately 70,000-90,000 refugees are resettled to the United States each year, and during the next 5 years, 50,000 Congolese refugees are expected to arrive in the United States. The International Organization for Migration (IOM) performs refugee medical examinations overseas for the U.S. Refugee Resettlement Program. In 2014, IOM reported that a large number of U.S.-bound Congolese refugees from Uganda had spleens that were enlarged on examination. During two evaluations of refugee populations in western Uganda in March and July 2015, refugees with splenomegaly on physical examination were offered additional assessment and treatment, including abdominal ultrasonography and laboratory testing. Among 987 persons screened, 145 (14.7%) had splenomegaly and received further testing. Among the 145 patients with splenomegaly, 63.4% were aged 5-17 years (median = 14.8 years). There was some evidence of family clustering, with 33 (22.7%) of the 145 cases occurring in families. |
Economic analysis of the impact of overseas and domestic treatment and screening options for intestinal helminth infection among US-bound refugees from Asia
Maskery B , Coleman MS , Weinberg M , Zhou W , Rotz L , Klosovsky A , Cantey PT , Fox LM , Cetron MS , Stauffer WM . PLoS Negl Trop Dis 2016 10 (8) e0004910 BACKGROUND: Many U.S.-bound refugees travel from countries where intestinal parasites (hookworm, Trichuris trichuria, Ascaris lumbricoides, and Strongyloides stercoralis) are endemic. These infections are rare in the United States and may be underdiagnosed or misdiagnosed, leading to potentially serious consequences. This evaluation examined the costs and benefits of combinations of overseas presumptive treatment of parasitic diseases vs. domestic screening/treating vs. no program. METHODS: An economic decision tree model terminating in Markov processes was developed to estimate the cost and health impacts of four interventions on an annual cohort of 27,700 U.S.-bound Asian refugees: 1) "No Program," 2) U.S. "Domestic Screening and Treatment," 3) "Overseas Albendazole and Ivermectin" presumptive treatment, and 4) "Overseas Albendazole and Domestic Screening for Strongyloides". Markov transition state models were used to estimate long-term effects of parasitic infections. Health outcome measures (four parasites) included outpatient cases, hospitalizations, deaths, life years, and quality-adjusted life years (QALYs). RESULTS: The "No Program" option is the least expensive ($165,923 per cohort) and least effective option (145 outpatient cases, 4.0 hospitalizations, and 0.67 deaths discounted over a 60-year period for a one-year cohort). The "Overseas Albendazole and Ivermectin" option ($418,824) is less expensive than "Domestic Screening and Treatment" ($3,832,572) or "Overseas Albendazole and Domestic Screening for Strongyloides" ($2,182,483). According to the model outcomes, the most effective treatment option is "Overseas Albendazole and Ivermectin," which reduces outpatient cases, deaths and hospitalization by around 80% at an estimated net cost of $458,718 per death averted, or $2,219/$24,036 per QALY/life year gained relative to "No Program". DISCUSSION: Overseas presumptive treatment for U.S.-bound refugees is a cost-effective intervention that is less expensive and at least as effective as domestic screening and treatment programs. The addition of ivermectin to albendazole reduces the prevalence of chronic strongyloidiasis and the probability of rare, but potentially fatal, disseminated strongyloidiasis. |
Detection of Onchocerca volvulus in Skin Snips by Microscopy and Real-Time Polymerase Chain Reaction: Implications for Monitoring and Evaluation Activities.
Thiele EA , Cama VA , Lakwo T , Mekasha S , Abanyie F , Sleshi M , Kebede A , Cantey PT . Am J Trop Med Hyg 2016 94 (4) 906-11 ![]() Microscopic evaluation of skin biopsies is the monitoring and evaluation (M and E) method currently used by multiple onchocerciasis elimination programs in Africa. However, as repeated mass drug administration suppresses microfilarial loads, the sensitivity and programmatic utility of skin snip microscopy is expected to decrease. Using a pan-filarial real-time polymerase chain reaction with melt curve analysis (qPCR-MCA), we evaluated 1) the use of a single-step molecular assay for detecting and identifying Onchocerca volvulus microfilariae in residual skin snips and 2) the sensitivity of skin snip microscopy relative to qPCR-MCA. Skin snips were collected and examined with routine microscopy in hyperendemic regions of Uganda and Ethiopia (N = 500 each) and "residual" skin snips (tissue remaining after induced microfilarial emergence) were tested with qPCR-MCA. qPCR-MCA detected Onchocerca DNA in 223 residual snips: 139 of 147 microscopy(+) and 84 among microscopy(-) snips, suggesting overall sensitivity of microscopy was 62.3% (139/223) relative to qPCR-MCA (75.6% in Uganda and 28.6% in Ethiopia). These findings demonstrate the insufficient sensitivity of skin snip microscopy for reliable programmatic monitoring. Molecular tools such as qPCR-MCA can augment sensitivity and provide diagnostic confirmation of skin biopsies and will be useful for evaluation or validation of new onchocerciasis M and E tools. |
Indications and types of antibiotic agents used in 6 acute care hospitals, 2009-2010: A pragmatic retrospective observational study
Kelesidis T , Braykov N , Uslan DZ , Morgan DJ , Gandra S , Johannsson B , Schweizer ML , Weisenberg SA , Young H , Cantey J , Perencevich E , Septimus E , Srinivasan A , Laxminarayan R . Infect Control Hosp Epidemiol 2016 37 (1) 70-9 BACKGROUND: To design better antimicrobial stewardship programs, detailed data on the primary drivers and patterns of antibiotic use are needed. OBJECTIVE: To characterize the indications for antibiotic therapy, agents used, duration, combinations, and microbiological justification in 6 acute-care US facilities with varied location, size, and type of antimicrobial stewardship programs. DESIGN, PARTICIPANTS, AND SETTING: Retrospective medical chart review was performed on a random cross-sectional sample of 1,200 adult inpatients, hospitalized (>24 hrs) in 6 hospitals, and receiving at least 1 antibiotic dose on 4 index dates chosen at equal intervals through a 1-year study period (October 1, 2009-September 30, 2010). METHODS: Infectious disease specialists recorded patient demographic characteristics, comorbidities, microbiological and radiological testing, and agents used, dose, duration, and indication for antibiotic prescriptions. RESULTS: On the index dates 4,119 (60.5%) of 6,812 inpatients were receiving antibiotics. The random sample of 1,200 case patients was receiving 2,527 antibiotics (average: 2.1 per patient); 540 (21.4%) were prophylactic and 1,987 (78.6%) were therapeutic, of which 372 (18.7%) were pathogen-directed at start. Of the 1,615 empirical starts, 382 (23.7%) were subsequently pathogen-directed and 1,231 (76.2%) remained empirical. Use was primarily for respiratory (27.6% of prescriptions) followed by gastrointestinal (13.1%) infections. Fluoroquinolones, vancomycin, and antipseudomonal penicillins together accounted for 47.1% of therapy-days. CONCLUSIONS: Use of broad-spectrum empirical therapy was prevalent in 6 US acute care facilities and in most instances was not subsequently pathogen directed. Fluoroquinolones, vancomycin, and antipseudomonal penicillins were the most frequently used antibiotics, particularly for respiratory indications. |
Chorioamnionitis and culture-confirmed, early-onset neonatal infections
Wortham JM , Hansen NI , Schrag SJ , Hale E , Van Meurs K , Sanchez PJ , Cantey JB , Faix R , Poindexter B , Goldberg R , Bizzarro M , Frantz I , Das A , Benitz WE , Shane AL , Higgins R , Stoll BJ . Pediatrics 2015 137 (1) BACKGROUND: Current guidelines for prevention of neonatal group B streptococcal disease recommend diagnostic evaluations and empirical antibiotic therapy for well-appearing, chorioamnionitis-exposed newborns. Some clinicians question these recommendations, citing the decline in early-onset group B streptococcal disease rates since widespread intrapartum antibiotic prophylaxis implementation and potential antibiotic risks. We aimed to determine whether chorioamnionitis-exposed newborns with culture-confirmed, early-onset infections can be asymptomatic at birth. METHODS: Multicenter, prospective surveillance for early-onset neonatal infections was conducted during 2006-2009. Early-onset infection was defined as isolation of a pathogen from blood or cerebrospinal fluid collected ≤72 hours after birth. Maternal chorioamnionitis was defined by clinical diagnosis in the medical record or by histologic diagnosis by placental pathology. Hospital records of newborns with early-onset infections born to mothers with chorioamnionitis were reviewed retrospectively to determine symptom onset. RESULTS: Early-onset infections were diagnosed in 389 of 396 586 live births, including 232 (60%) chorioamnionitis-exposed newborns. Records for 229 were reviewed; 29 (13%) had no documented symptoms within 6 hours of birth, including 21 (9%) who remained asymptomatic at 72 hours. Intrapartum antibiotic prophylaxis exposure did not differ significantly between asymptomatic and symptomatic infants (76% vs 69%; P = .52). Assuming complete guideline implementation, we estimated that 60 to 1400 newborns would receive diagnostic evaluations and antibiotics for each infected asymptomatic newborn, depending on chorioamnionitis prevalence. CONCLUSIONS: Some infants born to mothers with chorioamnionitis may have no signs of sepsis at birth despite having culture-confirmed infections. Implementation of current clinical guidelines may result in early diagnosis, but large numbers of uninfected asymptomatic infants would be treated. |
The emergence of zoonotic Onchocerca lupi infection in the United States - a case-series
Cantey PT , Weeks J , Edwards M , Rao S , Ostovar GA , Dehority W , Alzona M , Swoboda S , Christiaens B , Ballan W , Hartley J , Terranella A , Weatherhead J , Dunn JJ , Marx DP , Hicks MJ , Rauch RA , Smith C , Dishop MK , Handler MH , Dudley RW , Chundu K , Hobohm D , Feiz-Erfan I , Hakes J , Berry RS , Stepensaski S , Greenfield B , Shroeder L , Bishop H , de Aleida M , Mathison B , Eberhard M . Clin Infect Dis 2015 62 (6) 778-83 This case-series describes the six human infections with Onchocerca lupi, a parasite known to infect cats and dogs, that have been identified in the United States since 2013. Unlike cases reported outside the country, the American patients have not had subconjunctival nodules but have manifested more invasive disease (e.g. spinal, orbital, and subdermal nodules). Diagnosis remains challenging in the absence of a serologic test. Treatment should be guided by what is done for Onchocerca volvulus as there are no data for O. lupi. Available evidence suggests that there may be transmission in southwestern United States, but the risk of transmission to humans is not known. Research is needed to better define the burden of disease in the United States and develop appropriately-targeted prevention strategies. |
Contact tracing activities during the Ebola virus disease epidemic in Kindia and Faranah, Guinea, 2014
Dixon MG , Taylor MM , Dee J , Hakim A , Cantey P , Lim T , Bah H , Camara SM , Ndongmo CB , Togba M , Toure LY , Bilivogui P , Sylla M , Kinzer M , Coronado F , Tongren JE , Swaminathan M , Mandigny L , Diallo B , Seyler T , Rondy M , Rodier G , Perea WA , Dahl B . Emerg Infect Dis 2015 21 (11) 2022-8 The largest recorded Ebola virus disease epidemic began in March 2014; as of July 2015, it continued in 3 principally affected countries: Guinea, Liberia, and Sierra Leone. Control efforts include contact tracing to expedite identification of the virus in suspect case-patients. We examined contact tracing activities during September 20-December 31, 2014, in 2 prefectures of Guinea using national and local data about case-patients and their contacts. Results show less than one third of case-patients (28.3% and 31.1%) were registered as contacts before case identification; approximately two thirds (61.1% and 67.7%) had no registered contacts. Time to isolation of suspected case-patients was not immediate (median 5 and 3 days for Kindia and Faranah, respectively), and secondary attack rates varied by relationships of persons who had contact with the source case-patient and the type of case-patient to which a contact was exposed. More complete contact tracing efforts are needed to augment control of this epidemic. |
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