Last data update: Jun 03, 2024. (Total: 46935 publications since 2009)
Records 1-12 (of 12 Records) |
Query Trace: Tongren JE [original query] |
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Evidence for a role of Anopheles stephensi in the spread of drug and diagnosis-resistant malaria in Africa
Emiru T , Getachew D , Murphy M , Sedda L , Ejigu LA , Bulto MG , Byrne I , Demisse M , Abdo M , Chali W , Elliott A , Vickers EN , Aranda-Díaz A , Alemayehu L , Behaksera SW , Jebessa G , Dinka H , Tsegaye T , Teka H , Chibsa S , Mumba P , Girma S , Hwang J , Yoshimizu M , Sutcliffe A , Taffese HS , Bayissa GA , Zohdy S , Tongren JE , Drakeley C , Greenhouse B , Bousema T , Tadesse FG . Nat Med 2023 29 (12) 3203-3211 Anopheles stephensi, an Asian malaria vector, continues to expand across Africa. The vector is now firmly established in urban settings in the Horn of Africa. Its presence in areas where malaria resurged suggested a possible role in causing malaria outbreaks. Here, using a prospective case-control design, we investigated the role of An. stephensi in transmission following a malaria outbreak in Dire Dawa, Ethiopia in April-July 2022. Screening contacts of patients with malaria and febrile controls revealed spatial clustering of Plasmodium falciparum infections around patients with malaria in strong association with the presence of An. stephensi in the household vicinity. Plasmodium sporozoites were detected in these mosquitoes. This outbreak involved clonal propagation of parasites with molecular signatures of artemisinin and diagnostic resistance. To our knowledge, this study provides the strongest evidence so far for a role of An. stephensi in driving an urban malaria outbreak in Africa, highlighting the major public health threat posed by this fast-spreading mosquito. |
Notes from the field: Locally acquired mosquito-transmitted (autochthonous) plasmodium falciparum malaria - national capital region, Maryland, August 2023
Duwell M , DeVita T , Torpey D , Chen J , Myers RA , Mace K , Ridpath AD , Odongo W , Raphael BH , Lenhart A , Tongren JE , Stanley S , Blythe D . MMWR Morb Mortal Wkly Rep 2023 72 (41) 1123-1125 Although malaria was eliminated in the United States in the mid-1950s, approximately 2,000 malaria cases are imported into the United States from regions with endemic disease transmission each year, including approximately 200 in Maryland* (Figure) (1). Anopheles mosquito species that can transmit malaria exist in many areas in the United States (2). Locally acquired mosquito-transmitted (i.e., autochthonous) cases have not been identified since 2003; however, these imported cases represent a potential source of infection. In mid-2023, eight autochthonous malaria cases (Plasmodium vivax) were identified in Florida and Texas (3); in both states, the autochthonous cases occurred in the vicinity of an imported malaria case. |
Estimating malaria transmission risk through surveillance of human-vector interactions in northern Ghana
Coleman S , Yihdego Y , Gyamfi F , Kolyada L , Tongren JE , Zigirumugabe S , Dery DB , Badu K , Obiri-Danso K , Boakye D , Szumlas D , Armistead JS , Dadzie SK . Parasit Vectors 2023 16 (1) 205 BACKGROUND: Vector bionomics are important aspects of vector-borne disease control programs. Mosquito-biting risks are affected by environmental, mosquito behavior and human factors, which are important for assessing exposure risk and intervention impacts. This study estimated malaria transmission risk based on vector-human interactions in northern Ghana, where indoor residual spraying (IRS) and insecticide-treated nets (ITNs) have been deployed. METHODS: Indoor and outdoor human biting rates (HBRs) were measured using monthly human landing catches (HLCs) from June 2017 to April 2019. Mosquitoes collected were identified to species level, and Anopheles gambiae sensu lato (An. gambiae s.l.) samples were examined for parity and infectivity. The HBRs were adjusted using mosquito parity and human behavioral observations. RESULTS: Anopheles gambiae was the main vector species in the IRS (81%) and control (83%) communities. Indoor and outdoor HBRs were similar in both the IRS intervention (10.6 vs. 11.3 bites per person per night [b/p/n]; z = -0.33, P = 0.745) and control communities (18.8 vs. 16.4 b/p/n; z = 1.57, P = 0.115). The mean proportion of parous An. gambiae s.l. was lower in IRS communities (44.6%) than in control communities (71.7%). After adjusting for human behavior observations and parity, the combined effect of IRS and ITN utilization (IRS: 37.8%; control: 57.3%) on reducing malaria transmission risk was 58% in IRS + ITN communities and 27% in control communities with ITNs alone (z = -4.07, P < 0.001). However, this also revealed that about 41% and 31% of outdoor adjusted bites in IRS and control communities respectively, occurred before bed time (10:00 pm). The mean directly measured annual entomologic inoculation rates (EIRs) during the study were 6.1 infective bites per person per year (ib/p/yr) for IRS communities and 16.3 ib/p/yr for control communities. After considering vector survival and observed human behavior, the estimated EIR for IRS communities was 1.8 ib/p/yr, which represents about a 70% overestimation of risk compared to the directly measured EIR; for control communities, it was 13.6 ib/p/yr (16% overestimation). CONCLUSION: Indoor residual spraying significantly impacted entomological indicators of malaria transmission. The results of this study indicate that vector bionomics alone do not provide an accurate assessment of malaria transmission exposure risk. By accounting for human behavior parameters, we found that high coverage of ITNs alone had less impact on malaria transmission indices than combining ITNs with IRS, likely due to observed low net use. Reinforcing effective communication for behavioral change in net use and IRS could further reduce malaria transmission. |
The potential impact of anopheles stephensi establishment on the transmission of plasmodium falciparum in Ethiopia and prospective control measures
Hamlet A , Dengela D , Tongren JE , Tadesse FG , Bousema T , Sinka M , Seyoum A , Irish SR , Armistead JS , Churcher T . BMC Med 2022 20 (1) 135 BACKGROUND: Sub-Saharan Africa has seen substantial reductions in cases and deaths due to malaria over the past two decades. While this reduction is primarily due to an increasing expansion of interventions, urbanisation has played its part as urban areas typically experience substantially less malaria transmission than rural areas. However, this may be partially lost with the invasion and establishment of Anopheles stephensi. A. stephensi, the primary urban malaria vector in Asia, was first detected in Africa in 2012 in Djibouti and was subsequently identified in Ethiopia in 2016, and later in Sudan and Somalia. In Djibouti, malaria cases have increased 30-fold from 2012 to 2019 though the impact in the wider region remains unclear. METHODS: Here, we have adapted an existing model of mechanistic malaria transmission to estimate the increase in vector density required to explain the trends in malaria cases seen in Djibouti. To account for the observed plasticity in An. stephensi behaviour, and the unknowns of how it will establish in a novel environment, we sample behavioural parameters in order to account for a wide range of uncertainty. This quantification is then applied to Ethiopia, considering temperature-dependent extrinsic incubation periods, pre-existing vector-control interventions and Plasmodium falciparum prevalence in order to assess the potential impact of An. stephensi establishment on P. falciparum transmission. Following this, we estimate the potential impact of scaling up ITN (insecticide-treated nets)/IRS (indoor residual spraying) and implementing piperonyl butoxide (PBO) ITNs and larval source management, as well as their economic costs. RESULTS: We estimate that annual P. falciparum malaria cases could increase by 50% (95% CI 14-90) if no additional interventions are implemented. The implementation of sufficient control measures to reduce malaria transmission to pre-stephensi levels will cost hundreds of millions of USD. CONCLUSIONS: Substantial heterogeneity across the country is predicted and large increases in vector control interventions could be needed to prevent a major public health emergency. |
Partial indoor residual spraying with pirimiphos-methyl as an effective and cost-saving measure for the control of Anopheles gambiae s.l. in northern Ghana
Coleman S , Yihdego Y , Sherrard-Smith E , Thomas CS , Dengela D , Oxborough RM , Dadzie SK , Boakye D , Gyamfi F , Obiri-Danso K , Johns B , Siems LV , Lucas B , Tongren JE , Zigirumugabe S , Dery D , Fornadel C , George K , Belemvire A , Carlson J , Irish SR , Armistead JS , Seyoum A . Sci Rep 2021 11 (1) 18055 The scale up of indoor residual spraying (IRS) and insecticide treated nets have contributed significantly to global reductions in malaria prevalence over the last two decades. However, widespread pyrethroid resistance has necessitated the use of new and more expensive insecticides for IRS. Partial IRS with pirimiphos-methyl in experimental huts and houses in a village-wide trial was evaluated against Anopheles gambiae s.l. in northern Ghana. Four different scenarios in which either only the top or bottom half of the walls of experimental huts were sprayed, with or without also spraying the ceiling were compared. Mortality of An. gambiae s.l. on partially sprayed walls was compared with the standard procedures in which all walls and ceiling surfaces are sprayed. A small-scale trial was then conducted to assess the effectiveness, feasibility, and cost of spraying only the upper walls and ceiling as compared to full IRS and no spraying in northern Ghana. Human landing catches were conducted to estimate entomological indices and determine the effectiveness of partial IRS. An established transmission dynamics model was parameterized by an analysis of the experimental hut data and used to predict the epidemiological impact and cost effectiveness of partial IRS for malaria control in northern Ghana. In the experimental huts, partial IRS of the top (IRR 0.89, p = 0.13) or bottom (IRR 0.90, p = 0.15) half of walls and the ceiling was not significantly less effective than full IRS in terms of mosquito mortality. In the village trial, the annual entomological inoculation rate was higher for the unsprayed control (217 infective bites/person/year (ib/p/yr)) compared with the fully and partially sprayed sites, with 28 and 38 ib/p/yr, respectively. The transmission model predicts that the efficacy of partial IRS against all-age prevalence of malaria after six months would be broadly equivalent to a full IRS campaign in which 40% reduction is expected relative to no spray campaign. At scale, partial IRS in northern Ghana would have resulted in a 33% cost savings ($496,426) that would enable spraying of 36,000 additional rooms. These findings suggest that partial IRS is an effective, feasible, and cost saving approach to IRS that could be adopted to sustain and expand implementation of this key malaria control intervention. |
Impact evaluation of malaria control interventions on morbidity and all-cause child mortality in Rwanda, 2000-2010
Eckert E , Florey LS , Tongren JE , Salgado SR , Rukundo A , Habimana JP , Hakizimana E , Munguti K , Umulisa N , Mulindahabi M , Karema C . Am J Trop Med Hyg 2017 97 99-110 The impressive decline in child mortality that occurred in Rwanda from 1996-2000 to 2006-2010 coincided with a period of rapid increase of malaria control interventions such as indoor residual spraying (IRS); insecticide-treated net (ITN) distribution and use, and improved malaria case management. The impact of these interventions was examined through ecological correlation analysis, and robust decomposition analysis of contextual factors on all-cause child mortality. Child mortality fell 61% during the evaluation period and prevalence of severe anemia in children 6-23 months declined 71% between 2005 and 2010. These changes in malaria morbidity and mortality occurred concurrently with a substantial increase in vector control activities. ITN use increased among children under five, from 4% to 70%. The IRS program began in 2007 and covered 1.3 million people in the highest burden districts by 2010. At the same time, diagnosis and treatment with an effective antimalarial expanded nationally, and included making services available to children under the age of 5 at the community level. The percentage of children under 5 who sought care for a fever increased from 26% in 2000 to 48% in 2010. Multivariable models of the change in child mortality between 2000 and 2010 using nationally representative data reveal the importance of increasing ITN ownership in explaining the observed mortality declines. Taken as a whole, the evidence supports the conclusion that malaria control interventions contributed to the observed decline in child mortality in Rwanda from 2000 to 2010, even in a context of improving socioeconomic, maternal, and child health conditions. |
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. |
Injury prevention practices as depicted in G- and PG-rated movies, 2008-2012
Pelletier AR , Tongren JE , Gilchrist J . J Community Health 2014 40 (4) 613-8 Unintentional injuries are the leading cause of death among children in the United States. The use of recommended safety practices can reduce injuries. Children often learn behaviors from media exposure. Children's movies released in 1995-2007 infrequently depicted appropriate injury prevention practices. The aim of this study was to determine if injury prevention practices in children's movies have improved. The top grossing 25 G- and PG-rated movies in the United States per year for 2008-2012 were eligible for inclusion in the study. Movies or scenes were excluded if they were animated, not set in the present day, fantasy, documentary, or not in English. Injury prevention practices involving riding in a motor vehicle, walking, boating, bicycling, and four other activities were recorded for characters with speaking roles. Fifty-six (45 %) of the 125 movies met the inclusion criteria. A total of 603 person-scenes were examined involving 175 (29 %) children and 428 (71 %) adults. Thirty-eight person-scenes involved crashes or falls, resulting in four injuries and no deaths. Overall, 59 % (353/603) of person-scenes showed appropriate injury prevention practices. This included 313 (70 %) of 445 motor-vehicle passengers who were belted; 15 (30 %) of 50 pedestrians who used a crosswalk, 2 (7 %) of 30 boaters who wore personal flotation devices, and 8 (29 %) of 28 bicyclists who wore helmets. In comparison with previous studies, there were significant increases in usage of seat belts, crosswalks, personal flotation devices, and bicycle helmets. However, 41 % of person-scenes still showed unsafe practices and the consequences of those behaviors were infrequently depicted. |
Monitoring long-lasting insecticidal net (LLIN) durability to validate net serviceable life assumptions, in Rwanda
Hakizimana E , Cyubahiro B , Rukundo A , Kabayiza A , Mutabazi A , Beach R , Patel R , Tongren JE , Karema C . Malar J 2014 13 344 BACKGROUND: To validate assumptions about the length of the distribution-replacement cycle for long-lasting insecticidal nets (LLINs) in Rwanda, the Malaria and other Parasitic Diseases Division, Rwanda Ministry of Health, used World Health Organization methods to independently confirm the three-year LLIN serviceable life span recommendation of WHO. METHODS: Approximately 3,000 coded LLINs, distributed as part of a national campaign, were monitored in six sites, by means of six-monthly visits to selected houses. Two indicators, survivorship/attrition, a measure of the number of nets remaining, and fabric integrity, the proportion of remaining nets in either 'good', 'serviceable' or 'needs replacement' condition, based on holes in the net material, were tracked. To validate the assumption that the intervention would remain effective for three years, LLIN coverage, calculated using either survivorship, or integrity, by removing nets in the 'needs replacement' category from the survivorship total, was compared with the predicted proportion of nets remaining, derived from a net loss model, that assumes an LLIN serviceable life of three years. RESULTS: After two years, there was close agreement between estimated LLIN survivorship at all sites, 75% (range 64-84%), and the predicted proportion of nets remaining, 75%. However, when integrity was considered, observed survivorship at all sites, declined to 42% (range 10-54%). CONCLUSIONS: More than half, 58%, of the LLINs fell into the 'needs replacement' category after two years. While these nets were counted for survivorship, they were judged to be of little-to-no benefit to a user. Therefore, when integrity was taken into account, survivorship was significantly lower than predicted, suggesting that net serviceable life was actually closer to two, rather than three years, and, by extension, that the impact of the intervention during year three of the LLIN distribution-replacement cycle could be well below that seen in years one and two. |
Endogenous galectin-3 controls experimental malaria in a species-specific manner
Toscano MA , Tongren JE , De Souza JB , Liu FT , Riley EM , Rabinovich GA . Parasite Immunol 2012 34 (7) 383-387 Galectins are evolutionarily conserved glycan-binding proteins with pleiotropic roles in innate and adaptive immune responses. Galectin-3 has been implicated in several immunological processes as well as in pathogen recognition through specific binding to glycosylated receptors on the surface of host cells or microorganisms. In spite of considerable evidence supporting a role for galectin-3 in host-pathogen interactions, the relevance of this lectin in the regulation of the host defence mechanisms in vivo is poorly understood. In this study, we analysed the impact of galectin-3 deficiency during infection with three distinct species of rodent malaria parasites, Plasmodium yoelii 17XNL, Plasmodium berghei ANKA and Plasmodium chabaudi AS. We found that galectin-3 deficiency showed a marginal effect on the course of parasitaemia during P. chabaudi infection, but did not alter the course of parasitaemia during P. berghei infection. However, lack of galectin-3 significantly reduced P. yoelii parasitaemia. This reduced parasitaemia in Lgals3(-/-) mice was consistent with higher titres of anti-P. yoelii MSP1(19) IgG2b isotype antibodies when compared with their wild-type counterparts. Our results reflect the complexity and singularity of host-pathogen interactions, indicating a species-specific role of endogenous galectin-3 in the control of parasite infections and the modulation of antibody responses. |
Use of alcohol-based hand sanitizers as a risk factor for norovirus outbreaks in long-term care facilities in northern New England: December 2006 to March 2007
Blaney DD , Daly ER , Kirkland KB , Tongren JE , Tassler Kelso P , Talbot EA . Am J Infect Control 2011 39 (4) 296-301 BACKGROUND: During December 2006 to March 2007, a substantial increase in norovirus illnesses was noted in northern New England. We sought to identify institutional risk factors for norovirus outbreaks in northern New England long-term care facilities (LTCFs). METHODS: State health departments in Maine, New Hampshire, and Vermont distributed surveys to infection preventionists at all LTCFs in their respective states. We collected information regarding facility attributes, routine staff use of alcohol-based hand sanitizer (ABHS) versus soap and water, facility cleaning practices, and occurrence of any acute gastroenteritis outbreaks during December 2006 to March 2007. Norovirus confirmation was conducted in public health laboratories. Data were analyzed with univariate and logistic regression methods. RESULTS: Of 160 facilities, 91 (60%) provided survey responses, with 61 facilities reporting 73 outbreaks; 29 were confirmed norovirus. Facilities reporting that staff were equally or more likely to use ABHS than soap and water for routine hand hygiene had higher odds of an outbreak than facilities with staff less likely to use ABHS (adjusted odds ratio, 6.06; 95% confidence interval: 1.44-33.99). CONCLUSION: This study suggests that preferential use of ABHS over soap and water for routine hand hygiene might be associated with increased risk of norovirus outbreaks in LTCFs. |
Injury-prevention practices as depicted in G- and PG-rated movies, 2003-2007
Tongren JE , Sites A , Zwicker K , Pelletier A . Pediatrics 2010 125 (2) 290-4 OBJECTIVE: Our goal was to determine if the depiction of injury-prevention practices in children's movies is different from what was reported from 2 earlier studies, which showed infrequent depiction of characters practicing recommended safety behaviors. METHODS: The top-grossing 25 domestic G-rated (general audience) and PG-rated (parental guidance suggested) movies per year for 2003-2007 were included in this study. Movies or scenes were excluded if they were animated, not set in the present day, fantasy, documentary, or not in English. Injury-prevention practices involving motor vehicles, pedestrians, boaters, and bicyclists were recorded for characters with speaking roles. RESULTS: Sixty-seven (54%) of 125 movies met the inclusion criteria for this study. A total of 958 person-scenes were examined: 524 (55%) depicted children and 434 (45%) adults. Twenty-two person-scenes involved crashes or falls, resulting in 3 injuries and no deaths. Overall, 311 (56%) of 555 motor-vehicle passengers were belted; 73 (35%) of 211 pedestrians used crosswalks; 60 (75%) of 80 boaters wore personal flotation devices; and 8 (25%) of 32 bicyclists wore helmets. In comparison with previous studies, usage of safety belts, crosswalks, personal flotation devices, and bicycle helmets increased significantly. CONCLUSIONS: The entertainment industry has improved the depiction of selected safety practices in G- and PG-rated movies. However, approximately one half of scenes still depict unsafe practices, and the consequences of these behaviors are rarely shown. The industry should continue to improve how it depicts safety practices in children's movies. Parents should highlight the depiction of unsafe behaviors and educate children in following safe practices. |
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