Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-17 (of 17 Records) |
Query Trace: Velayudhan A [original query] |
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Malaria outbreak investigation in a tribal area of Pratapgarh district, Rajasthan, India, 2016; Proceedings of 'FETP-ICON 2020' Conference : Chennai, India. 3-5 March 2020
Vaisakh T P , Kumar Rajeev , Mishra Abhishek , Babu Binoy S , Patel Purvi , Dikid Tanzin , Chandra Ramesh , Yadav Rajesh , Papanna Mohan , Velayudhan Anoop , Goel Saurabh , Dhandore Suhas , Shewale Ajit , Ponnaiah Manickam , Murhekar Manoj , Prasad Ravindra , Jain SK , Singh Sujeet . BMC Proc 2021 15 17 Acute encephalopathy syndrome (AES) is characterized by sudden onset of seizures and altered sensorium of infectious or non-infectious origin. Seasonal outbreaks of fatal hypoglycaemic AES in children, associated with eating fruit from the Sapindaceae family (e.g., ackee, litchi), have been reported globally [1,2]. Since 1995, AES outbreaks have been reported during the litchi-harvesting season from May–July in Muzaffarpur, the largest commercial litchi-producing district of Bihar, India [3]. An AES outbreak investigation in Muzaffarpur in 2014 linked known toxins hypoglycin A and α-methylene cyclopropyl glycine (MCPG) in litchi fruit to hypoglycaemic AES in children [3]. Following the 2014 outbreak, the Government of Bihar implemented community-based interventions to prevent hypoglycemia in children. They also strengthened the clinical management of hypoglycaemic seizures in public health facilities [4]. The number of AES cases and deaths declined from 2015–18, suggesting that the interventions were effective. However, in May–June 2019, AES cases increased. We conducted a descriptive epidemiological analysis of the AES cases. | | Methods | | We identified AES cases from established hospital-based surveillance in the two tertiary referral hospitals in Muzaffarpur. We defined a suspected AES case as seizures or altered sensorium in a child aged ≤15 years admitted from 1 May to 2nd July 2019. We excluded patients aged six months to 6 years who were admitted for fever and a single generalized convulsion of <15 minutes in duration and recovered consciousness within 60 minutes of seizure. We conducted a review of medical records and abstracted data using a structured tool for socio-demographics, clinical history, duration of hospitalization, treatment, and laboratory profile. We also assembled a prospective cohort of probable cases admitted to the hospital during the investigation. We defined a probable AES case as new-onset seizures or altered sensorium of <7 days duration in a child aged ≤15 years admitted t from 1 May to 2 July 2019. For the cohort of probable cases, we interviewed the caregivers using a structured clinical-epidemiological questionnaire for socio-demographics, anthropometry, illness characteristics, treatment-seeking behavior, meal assessment, exposure to litchi fruit, and exposure to health messages. For anthropometry, we calculated Z-scores using the World Health Organization 2006 standardized growth tables [5]. | | Results | | Of the 655 suspected and probable AES cases identified, the case fatality rate (CFR) was 21% (139 deaths). The median age was four years (interquartile range: 3 months–14 years), and 58% (378) were females. The first case was reported on 5 May 2019, cases peaked on 15 June, and the last case on 2 July (Figure 1). Among cases with available data, 75% (389/518) had blood glucose levels of <70 mg/dL upon hospital admission, and 75% (476/638) were residents of Muzaffarpur district. We identified cases from 15 (94%) of 16 blocks in the Muzaffarpur district and calculated a district incidence of 22 per 100,000 children ≤15 years old. | | The prospective cohort comprised 94 probable AES cases; CFR was 26%. Among probable cases, 63% (49/78) of caregivers were wage workers, and 34% (31/91) were of low socioeconomic status. Symptoms were reported in the early morning (3 am to 8 am) for 67% (62/93) of cases, and 97% (90/93) presented with seizures. Among probable cases with anthropometry data, 62% (43/69) were underweight (i.e., weight-for-age Z score <-2), 44% (25/57) stunted (i.e., height-for-age Z score <-2), and 43% (10/23) wasted (i.e., weight-for-height Z score <-2). Primary health facilities referred 46% (43/93) of probable cases to the two tertiary hospitals for admission. Among cases referred, only 30% (13/43) received hypoglycemia and seizure management at the primary health facility. | | Eating litchis in the 24 hours and seven days before illness onset was reported by 57% (54/94) and 87% (59/68) of caregivers, respectively. Skipping any meal and skipping the evening meal in the 24 hours before illness onset was reported by 55% (48/88) and 44% (28/63) of caregivers, respectively. Among probable cases, 45% (27/60) of caregivers reported Government Supplementary Nutrition (GSN) programme enrollment. Sixty percent (50/83) of caregivers said a visit by health workers in the week before illness. Still, only 8% (7/83) reported receiving messages on AES prevention and early treatment by health workers in the past month. | | Conclusions | | The 2019 AES outbreak in Muzaffarpur district, Bihar, occurred among young children with hypoglycemia upon hospital admission and had high associated mortality. Although the Government of Bihar implemented community and clinical measures to prevent AES cases after the 2014 outbreak, a large proportion of the AES cases did not benefit from the prevention measures based on our investigation [4]. New state and district health leadership, turnover of community and facility-level healthcare workers, lack of ongoing training and focused community outreach, and competing health priorities might have been factors responsible for the resurgence. To prevent future AES cases, we recommended prompt emergency management of hypoglycemia and seizures at primary health facilities before referral. We recommend enrollment of all eligible children to GSN and enhanced community health communications to reinforce the importance of an evening meal for children and limiting the eating of litchi fruit during the harvesting season from May to July |
A new WHO bottle bioassay method to assess the susceptibility of mosquito vectors to public health insecticides: results from a WHO-coordinated multi-centre study
Corbel V , Kont MD , Ahumada ML , Andréo L , Bayili B , Bayili K , Brooke B , Pinto Caballero JA , Lambert B , Churcher TS , Duchon S , Etang J , Flores AE , Gunasekaran K , Juntarajumnong W , Kirby M , Davies R , Lees RS , Lenhart A , Lima JBP , Martins AJ , Müller P , N'Guessan R , Ngufor C , Praulins G , Quinones M , Raghavendra K , Verma V , Rus AC , Samuel M , Ying KS , Sungvornyothin S , Uragayala S , Velayudhan R , Yadav RS . Parasit Vectors 2023 16 (1) 21 BACKGROUND: The continued spread of insecticide resistance in mosquito vectors of malaria and arboviral diseases may lead to operational failure of insecticide-based interventions if resistance is not monitored and managed efficiently. This study aimed to develop and validate a new WHO glass bottle bioassay method as an alternative to the WHO standard insecticide tube test to monitor mosquito susceptibility to new public health insecticides with particular modes of action, physical properties or both. METHODS: A multi-centre study involving 21 laboratories worldwide generated data on the susceptibility of seven mosquito species (Aedes aegypti, Aedes albopictus, Anopheles gambiae sensu stricto [An. gambiae s.s.], Anopheles funestus, Anopheles stephensi, Anopheles minimus and Anopheles albimanus) to seven public health insecticides in five classes, including pyrethroids (metofluthrin, prallethrin and transfluthrin), neonicotinoids (clothianidin), pyrroles (chlorfenapyr), juvenile hormone mimics (pyriproxyfen) and butenolides (flupyradifurone), in glass bottle assays. The data were analysed using a Bayesian binomial model to determine the concentration-response curves for each insecticide-species combination and to assess the within-bioassay variability in the susceptibility endpoints, namely the concentration that kills 50% and 99% of the test population (LC(50) and LC(99), respectively) and the concentration that inhibits oviposition of the test population by 50% and 99% (OI(50) and OI(99)), to measure mortality and the sterilizing effect, respectively. RESULTS: Overall, about 200,000 mosquitoes were tested with the new bottle bioassay, and LC(50)/LC(99) or OI(50)/OI(99) values were determined for all insecticides. Variation was seen between laboratories in estimates for some mosquito species-insecticide combinations, while other test results were consistent. The variation was generally greater with transfluthrin and flupyradifurone than with the other compounds tested, especially against Anopheles species. Overall, the mean within-bioassay variability in mortality and oviposition inhibition were < 10% for most mosquito species-insecticide combinations. CONCLUSION: Our findings, based on the largest susceptibility dataset ever produced on mosquitoes, showed that the new WHO bottle bioassay is adequate for evaluating mosquito susceptibility to new and promising public health insecticides currently deployed for vector control. The datasets presented in this study have been used recently by the WHO to establish 17 new insecticide discriminating concentrations (DCs) for either Aedes spp. or Anopheles spp. The bottle bioassay and DCs can now be widely used to monitor baseline insecticide susceptibility of wild populations of vectors of malaria and Aedes-borne diseases worldwide. |
Litchi consumption and missed meals continue to be associated with acute encephalopathy syndrome among children: an investigation of the 2019 outbreak in Muzaffarpur district, Bihar, India
Ponnaiah M , Dikid T , Yadav R , Thangaraj JWV , Velusamy S , Vaisakh TP , Babu B , Mishra A , Patel P , Papanna M , Velayudhan A , Sharma R , Shrivastava A , Jain SK , Prasad R , Kumar S , Singh V , Singh SK , Murhekar M . Trans R Soc Trop Med Hyg 2022 117 (1) 45-49 BACKGROUND: Muzaffarpur district in Bihar State of India recorded a resurgence of acute encephalopathy syndrome (AES) cases in the summer of 2019 after no reported outbreak in 3 y. Earlier studies generated evidence that litchi consumption and missing the previous evening's meal were associated with AES. We investigated the recent outbreak to understand the risk factors associated with AES. METHODS: We conducted a matched case-control study by comparing AES cases with healthy controls from case-households and the neighborhood community for risk factors like missing evening meal and litchi consumption before onset of AES. RESULTS: We recruited 61 cases and 239 controls. Compared with the community controls, case-patients were five times more likely to have reported eating litchi in the 7 d preceding the onset of illness (adjusted OR [AOR]=5.1; 95% CI 1.3 to 19) and skipping the previous evening's meal (AOR=5.2; 95% CI 1.4 to 20). Compared with household controls, case-patients were five times more likely to be children aged <5 y (AOR=5.3; 95% CI 1.3 to 22) and seven times more likely to have skipped the previous evening's meal (AOR=7.4; 95% CI 1.7 to 34). CONCLUSIONS: Skipping the previous evening's meal and litchi consumption were significantly associated with AES among children in Muzaffarpur and adjoining districts of Bihar. |
An outbreak of Burkholderia cepacia bloodstream infections in a tertiary-care facility in northern India detected by a healthcare-associated infection surveillance network
Fomda B , Velayudhan A , Siromany VA , Bashir G , Nazir S , Ali A , Katoch O , Karoung A , Gunjiyal J , Wani N , Roy I , VanderEnde D , Gupta N , Sharma A , Malpiedi P , Walia K , Mathur P . Infect Control Hosp Epidemiol 2022 44 (3) 1-7 OBJECTIVE: The burden of healthcare-associated infections (HAIs) is higher in low- and middle-income countries, but HAIs are often missed because surveillance is not conducted. Here, we describe the identification of and response to a cluster of Burkholderia cepacia complex (BCC) bloodstream infections (BSIs) associated with high mortality in a surgical ICU (SICU) that joined an HAI surveillance network. SETTING: A 780-bed, tertiary-level, public teaching hospital in northern India. METHODS: After detecting a cluster of BCC in the SICU, cases were identified by reviewing laboratory registers and automated identification and susceptibility testing outputs. Sociodemographic details, clinical records, and potential exposure histories were collected, and a self-appraisal of infection prevention and control (IPC) practices using assessment tools from the World Health Organization and the US Centers for Disease Control and Prevention was conducted. Training and feedback were provided to hospital staff. Environmental samples were collected from high-touch surfaces, intravenous medications, saline, and mouthwash. RESULTS: Between October 2017 and October 2018, 183 BCC BSI cases were identified. Case records were available for 121 case patients. Of these 121 cases, 91 (75%) were male, the median age was 35 years, and 57 (47%) died. IPC scores were low in the areas of technical guidelines, human resources, and monitoring and evaluation. Of the 30 environmental samples, 4 grew BCC. A single source of the outbreak was not identified. CONCLUSIONS: Implementing standardized HAI surveillance in a low-resource setting detected an ongoing Burkholderia cepacia outbreak. The outbreak investigation and use of a multimodal approach reduced incident cases and informed changes in IPC practices. |
An algorithmic approach to identifying the aetiology of acute encephalitis syndrome in India: results of a 4-year enhanced surveillance study
Ravi V , Hameed SKS , Desai A , Mani RS , Reddy V , Velayudhan A , Yadav R , Jain A , Saikia L , Borthakur AK , Sharma A , Mohan DG , Bhandopadhyay B , Bhattacharya N , Inamdar L , Hossain S , Daves S , Sejvar J , Dhariwal AC , Sen PK , Venkatesh S , Prasad J , Laserson K , Srikantiah P . Lancet Glob Health 2022 10 (5) e685-e693 BACKGROUND: Annual outbreaks of acute encephalitis syndrome pose a major health burden in India. Although Japanese encephalitis virus (JEV) accounts for around 15% of reported cases, the aetiology of most cases remains unknown. We aimed to establish an enhanced surveillance network and to use a standardised diagnostic algorithm to conduct a systematic evaluation of acute encephalitis syndrome in India. METHODS: In this large-scale, systematic surveillance study in India, patients presenting with acute encephalitis syndrome (ie, acute onset of fever with altered mental status, seizure, or both) to any of the 18 participating hospitals across Uttar Pradesh, West Bengal, and Assam were evaluated for JEV (serum and cerebrospinal fluid [CSF] IgM ELISA) per standard of care. In enhanced surveillance, JEV IgM-negative specimens were additionally evaluated for scrub typhus, dengue virus, and West Nile virus by serum IgM ELISA, and for Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, dengue virus, herpes simplex virus, and enterovirus by CSF PCR across five referral laboratories. In 2017, chikungunya and Leptospira serum IgM by ELISA and Zika virus serum and CSF by PCR were also tested. FINDINGS: Of 10107 patients with acute encephalitis syndrome enrolled in enhanced surveillance between Jan 1, 2014, and Dec 31, 2017, 5734 (578%) of 9917 participants with available data were male and 6179 (627%) of 9856 were children aged 15 years and younger. Among patients who provided a sample of either CSF or serum in enhanced surveillance, an aetiology was identified in 1921 (332%) of 5786 patients enrolled between 2014 and 2016 and in 1484 (343%) of 4321 patients enrolled in 2017. The most commonly identified aetiologies were JEV (1023 [177%] of 5786 patients), scrub typhus (645 [185%] of 3489), and dengue virus (161 [52%] of 3124). Among participants who provided both CSF and serum specimens, an aetiology was identified in 1446 (383%) of 3774 patients enrolled between 2014 and 2016 and in 936 (403%) of 2324 enrolled in 2017, representing a 31-times increase in the number of patients with acute encephalitis syndrome with an identified aetiology compared with standard care alone (299 [129%]; p<00001). INTERPRETATION: Implementation of a systematic diagnostic algorithm in an enhanced surveillance platform resulted in a 31-times increase in identification of the aetiology of acute encephalitis syndrome, besides JEV alone, and highlighted the importance of scrub typhus and dengue virus as important infectious aetiologies in India. These findings have prompted revision of the national testing guidelines for this syndrome across India. FUNDING: US Centers for Disease Control and Prevention. |
Shellfish poisoning outbreaks in Cuddalore District, Tamil Nadu, India.
Velayudhan A , Nayak J , Murhekar MV , Dikid T , Sodha SV . Indian J Public Health 2021 65 S29-s33 BACKGROUND: Two suspected shellfish poisoning events were reported in Cuddalore District in Tamil Nadu, India, between January and April 2015. OBJECTIVES: The study was conducted to confirm the outbreaks and to identify the source and risk factors. METHODS: For both outbreaks, a case was defined as a person with nausea, vomiting, or dizziness. Sociodemographic details and symptoms were noted down. Data were also collected in a standard 3-day food frequency questionnaire, along with a collection of clam samples. A case-control study was initiated in the April outbreak. Stool samples were collected from cases, and clam vendors were interviewed. RESULTS: In an outbreak that happened in January, all the twenty people reported to be consumed clams were diagnosed as cases (100% attack rate, 100% exposure rate). In the April outbreak, we identified 199 cases (95% attack rate). In both outbreaks, the clams were identified as genus Meretrix meretrix. The most common reported symptoms were dizziness and vomiting. The clams heated and consumed within 30-60 min. No heavy metals or chemicals were detected in the clams, but assays for testing shellfish toxins were unavailable. All 64 selected cases reported clam consumption (100% exposure rate) as did 11 controls (17% exposure rate). Illness was associated with a history of eating of clams (odds ratio = 314, 95% confidence interval = 39-512). Of the six stool samples tested, all were culture negative for Salmonella, Shigella, and Vibrio cholerae. The water at both sites was contaminated with garbage and sewage. CONCLUSION: Coordinated and timely efforts by a multidisciplinary team of epidemiologists, marine biologists, and food safety officers led to the outbreaks' containment. |
Outbreak investigation of foodborne illness among political rally attendees, Cuddalore, Tamil Nadu, India
Patil AA , Velayudhan A , Durairaj GK , Khasnobis P , Sodha SV . Indian J Public Health 2021 65 S55-s58 In July 2015, we investigated a foodborne illness outbreak in Sithalikuppam and Verupachi villages, Cuddalore district, Tamil Nadu, among the political rally attendees to determine the risk factors for illness. We conducted a retrospective cohort study, calculated risk ratio for the food exposures, and cultured stool specimens. Of 55 rally attendees, we identified 36 (65%) case patients; 32 (89%) had diarrhea and 20 (56%) had vomiting. Median incubation period was 14 h. Eighty-nine percent (32/36) of those who ate lemon rice at dinner had illness compared to 21% (4/19) of those who did not (RR 4.2). Of the six nonattendees who ate leftovers on July 25, all ate only lemon rice and became ill. Stool cultures were negative for Salmonella, Shigella, and Vibrio species. Lemon rice was probably contaminated with enterotoxins such as from Bacillus cereus. Our findings highlighted need for community food safety education and importance of thorough outbreak investigations. |
Multiple importations and transmission of colistin-resistant Klebsiella pneumoniae in a hospital in northern India.
Mathur P , Khurana S , de Man TJB , Rastogi N , Katoch O , Veeraraghavan B , Neeravi AR , Venkatesan M , Kumar S , Sagar S , Gupta A , Aggarwal R , Soni KD , Malhotra R , Velayudhan A , Siromany V , Malpiedi P , Lutgring J , Laserson K , Gupta N , Srikantiah P , Sharma A . Infect Control Hosp Epidemiol 2019 40 (12) 1-7 OBJECTIVE: Resistance to colistin, a last resort antibiotic, has emerged in India. We investigated colistin-resistant Klebsiella pneumoniae(ColR-KP) in a hospital in India to describe infections, characterize resistance of isolates, compare concordance of detection methods, and identify transmission events. DESIGN: Retrospective observational study. METHODS: Case-patients were defined as individuals from whom ColR-KP was isolated from a clinical specimen between January 2016 and October 2017. Isolates resistant to colistin by Vitek 2 were confirmed by broth microdilution (BMD). Isolates underwent colistin susceptibility testing by disk diffusion and whole-genome sequencing. Medical records were reviewed. RESULTS: Of 846 K. pneumoniae isolates, 34 (4%) were colistin resistant. In total, 22 case-patients were identified. Most (90%) were male; their median age was 33 years. Half were transferred from another hospital; 45% died. Case-patients were admitted for a median of 14 days before detection of ColR-KP. Also, 7 case-patients (32%) received colistin before detection of ColR-KP. All isolates were resistant to carbapenems and susceptible to tigecycline. Isolates resistant to colistin by Vitek 2 were also resistant by BMD; 2 ColR-KP isolates were resistant by disk diffusion. Moreover, 8 multilocus sequence types were identified. Isolates were negative for mobile colistin resistance (mcr) genes. Based on sequencing analysis, in-hospital transmission may have occurred with 8 case-patients (38%). CONCLUSIONS: Multiple infections caused by highly resistant, mcr-negative ColR-KP with substantial mortality were identified. Disk diffusion correlated poorly with Vitek 2 and BMD for detection of ColR-KP. Sequencing indicated multiple importation and in-hospital transmission events. Enhanced detection for ColR-KP may be warranted in India. |
Dengue virus is an under-recognised causative agent of acute encephalitis syndrome (AES): Results from a four year AES surveillance study of Japanese encephalitis in selected states of IndiaDengue virus is an under-recognised causative
Ravi V , Hameed SKS , Desai A , Mani RS , Reddy V , Velayudhan A , Yadav R , Jain A , Saikia L , Borthakur AK , Mohan DG , Bhandopadhyay B , Bhattacharya N , Dhariwal AC , Sen PK , Venkatesh S , Prasad J , Laserson K , Srikantiah P . Int J Infect Dis 2019 84S S19-S24 BACKGROUND: Acute encephalitis syndrome (AES) surveillance in India has indicated that Japanese encephalitis virus (JEV) accounts for 5-35% of AES cases annually; the etiology remains unknown in the remaining cases. We implemented comprehensive AES surveillance to identify other etiological agents of AES, with emphasis on dengue virus. METHODS: Serum and cerebrospinal fluid (CSF) specimens were collected from patients enrolled prospectively in AES surveillance from 2014-2017 at selected sites of three high burden states of India. All samples were initially tested for JEV IgM. Specimens negative for JEV by serology were tested for IgM to scrub typhus, dengue virus (DEN), and West Nile virus; all JEV IgM-negative CSF samples were tested by PCR for S.pneumoniae, N.meningitidis, H.influenzae, herpes simplex virus type 1, enteroviruses and DEN. RESULTS: Of 10,107 AES patients, an etiology could be established in 49.2% of patients including JEV (16%), scrub typus (16%) and DEN (5.2%) as the top three agents. Amongst the DEN positive cases (359/6892), seven (2%) were positive only for dengue virus RNA: one in serum and six in CSF. CONCLUSION: Amongst the pathogens identified, dengue accounted for 5% of all AES cases and was one of the three common etiological agents. These results underscore the importance of including dengue virus in routine testing of AES cases. |
Risk factors for acquiring scrub typhus among children in Deoria and Gorakhpur Districts, Uttar Pradesh, India, 2017
Thangaraj JWV , Vasanthapuram R , Machado L , Arunkumar G , Sodha SV , Zaman K , Bhatnagar T , Hameed SKS , Kumar A , Abdulmajeed J , Velayudhan A , Deoshatwar A , Desai AS , Kumar KH , Gupta N , Laserson K , Murhekar M . Emerg Infect Dis 2018 24 (12) 2364-2367 Scrub typhus is associated with outbreaks of acute encephalitis syndrome in Uttar Pradesh, India. A case-control study indicated that children residing, playing, or visiting fields; living with firewood stored indoors; handling cattle fodder; and practicing open defecation were at increased risk for scrub typhus. Communication messages should focus on changing these behaviors. |
Strengthening infection prevention and control and systematic surveillance of healthcare associated infections in India
Swaminathan S , Prasad J , Dhariwal AC , Guleria R , Misra MC , Malhotra R , Mathur P , Walia K , Gupta S , Sharma A , Ohri V , Jain S , Gupta N , Laserson K , Malpiedi P , Velayudhan A , Park B , Srikantiah P . BMJ 2017 358 j3768 Establishing and expanding government led networks to strengthen infection prevention and control and healthcare associated infection surveillance are essential to effectively tackle antimicrobial resistance. Soumya Swaminathan and colleagues discuss the progress in India |
International workshop on insecticide resistance in vectors of arboviruses, December 2016, Rio de Janeiro, Brazil
Corbel V , Fonseca DM , Weetman D , Pinto J , Achee NL , Chandre F , Coulibaly MB , Dusfour I , Grieco J , Juntarajumnong W , Lenhart A , Martins AJ , Moyes C , Ng LC , Raghavendra K , Vatandoost H , Vontas J , Muller P , Kasai S , Fouque F , Velayudhan R , Durot C , David JP . Parasit Vectors 2017 10 (1) 278 Vector-borne diseases transmitted by insect vectors such as mosquitoes occur in over 100 countries and affect almost half of the world's population. Dengue is currently the most prevalent arboviral disease but chikungunya, Zika and yellow fever show increasing prevalence and severity. Vector control, mainly by the use of insecticides, play a key role in disease prevention but the use of the same chemicals for more than 40 years, together with the dissemination of mosquitoes by trade and environmental changes, resulted in the global spread of insecticide resistance. In this context, innovative tools and strategies for vector control, including the management of resistance, are urgently needed. This report summarizes the main outputs of the first international workshop on Insecticide resistance in vectors of arboviruses held in Rio de Janeiro, Brazil, 5-8 December 2016. The primary aims of this workshop were to identify strategies for the development and implementation of standardized insecticide resistance management, also to allow comparisons across nations and across time, and to define research priorities for control of vectors of arboviruses. The workshop brought together 163 participants from 28 nationalities and was accessible, live, through the web (> 70,000 web-accesses over 3 days). |
Association of acute toxic encephalopathy with litchi consumption in an outbreak in Muzaffarpur, India, 2014: a case-control study
Shrivastava A , Kumar A , Thomas JD , Laserson KF , Bhushan G , Carter MD , Chhabra M , Mittal V , Khare S , Sejvar JJ , Dwivedi M , Isenberg SL , Johnson R , Pirkle JL , Sharer JD , Hall PL , Yadav R , Velayudhan A , Papanna M , Singh P , Somashekar D , Pradhan A , Goel K , Pandey R , Kumar M , Kumar S , Chakrabarti A , Sivaperumal P , Kumar AR , Schier JG , Chang A , Graham LA , Mathews TP , Johnson D , Valentin L , Caldwell KL , Jarrett JM , Harden LA , Takeoka GR , Tong S , Queen K , Paden C , Whitney A , Haberling DL , Singh R , Singh RS , Earhart KC , Dhariwal AC , Chauhan LS , Venkatesh S , Srikantiah P . Lancet Glob Health 2017 5 (4) e458-e466 BACKGROUND: Outbreaks of unexplained illness frequently remain under-investigated. In India, outbreaks of an acute neurological illness with high mortality among children occur annually in Muzaffarpur, the country's largest litchi cultivation region. In 2014, we aimed to investigate the cause and risk factors for this illness. METHODS: In this hospital-based surveillance and nested age-matched case-control study, we did laboratory investigations to assess potential infectious and non-infectious causes of this acute neurological illness. Cases were children aged 15 years or younger who were admitted to two hospitals in Muzaffarpur with new-onset seizures or altered sensorium. Age-matched controls were residents of Muzaffarpur who were admitted to the same two hospitals for a non-neurologic illness within seven days of the date of admission of the case. Clinical specimens (blood, cerebrospinal fluid, and urine) and environmental specimens (litchis) were tested for evidence of infectious pathogens, pesticides, toxic metals, and other non-infectious causes, including presence of hypoglycin A or methylenecyclopropylglycine (MCPG), naturally-occurring fruit-based toxins that cause hypoglycaemia and metabolic derangement. Matched and unmatched (controlling for age) bivariate analyses were done and risk factors for illness were expressed as matched odds ratios and odds ratios (unmatched analyses). FINDINGS: Between May 26, and July 17, 2014, 390 patients meeting the case definition were admitted to the two referral hospitals in Muzaffarpur, of whom 122 (31%) died. On admission, 204 (62%) of 327 had blood glucose concentration of 70 mg/dL or less. 104 cases were compared with 104 age-matched hospital controls. Litchi consumption (matched odds ratio [mOR] 9.6 [95% CI 3.6 - 24]) and absence of an evening meal (2.2 [1.2-4.3]) in the 24 h preceding illness onset were associated with illness. The absence of an evening meal significantly modified the effect of eating litchis on illness (odds ratio [OR] 7.8 [95% CI 3.3-18.8], without evening meal; OR 3.6 [1.1-11.1] with an evening meal). Tests for infectious agents and pesticides were negative. Metabolites of hypoglycin A, MCPG, or both were detected in 48 [66%] of 73 urine specimens from case-patients and none from 15 controls; 72 (90%) of 80 case-patient specimens had abnormal plasma acylcarnitine profiles, consistent with severe disruption of fatty acid metabolism. In 36 litchi arils tested from Muzaffarpur, hypoglycin A concentrations ranged from 12.4 mug/g to 152.0 mug/g and MCPG ranged from 44.9 mug/g to 220.0 mug/g. INTERPRETATION: Our investigation suggests an outbreak of acute encephalopathy in Muzaffarpur associated with both hypoglycin A and MCPG toxicity. To prevent illness and reduce mortality in the region, we recommended minimising litchi consumption, ensuring receipt of an evening meal and implementing rapid glucose correction for suspected illness. A comprehensive investigative approach in Muzaffarpur led to timely public health recommendations, underscoring the importance of using systematic methods in other unexplained illness outbreaks. FUNDING: US Centers for Disease Control and Prevention. |
Tracking insecticide resistance in mosquito vectors of arboviruses: the Worldwide Insecticide resistance Network (WIN)
Corbel V , Achee NL , Chandre F , Coulibaly MB , Dusfour I , Fonseca DM , Grieco J , Juntarajumnong W , Lenhart A , Martins AJ , Moyes C , Ng LC , Pinto J , Raghavendra K , Vatandoost H , Vontas J , Weetman D , Fouque F , Velayudhan R , David JP . PLoS Negl Trop Dis 2016 10 (12) e0005054 The transmission of the arboviral agents of dengue, yellow fever, Chikungunya, and Zika by Aedes mosquitoes represents expanding threats to global health. At the 69th World Health Assembly [1], the WHO Director-General Margaret Chan declared that the spread of the Zika virus was "the result of the abandon of mosquito control" by governments since the 1970s and urged Member States to mobilize more efforts and resources to prevent further spread of the diseases. The recent rise of microcephaly cases and other neurological disorders reported in Brazil prompted WHO to declare Zika as a Public Health Emergency of International Concern [2]. After limited early outbreaks in the Pacific in 2007 and 2013, the Zika virus has spread to more than 30 countries in the Americas and the Caribbean, affecting over 1.5 million people [3]. With growing evidence supporting the link between microcephaly and Zika [4, 5] and preliminary evidence confirming Aedes aegypti as the primary vector in the Brazilian outbreak [6], the mandate for control is clear and urgent. | Although progress is being made on vaccine development (for example, Sanofi Pasteur’s recently licensed dengue vaccine Dengvaxia [7]), vector control by removing larval habitats and using biological and chemical insecticides still remain the first line of defence against arboviruses [8]. Unfortunately, decades of efforts failed to consistently control Aedes mosquito populations and/or to curtail the cycle of epidemics. Control of adult mosquitoes using space spray applications of pyrethroids and organophospates in plural is fraught with complications, including high cost, slow operational response, low community buy-in, ineffective timing of application, and rather low efficacy and/or residual effect [9–11]. Furthermore, some countries have a lack of capacity in monitoring the use of public health insecticides for the control of arbovirus vectors [12] that is essential for guiding pesticide management systems on appropriate use and reduction of risks to human health and environment. |
Global distribution and environmental suitability for chikungunya virus, 1952 to 2015.
Nsoesie EO , Kraemer MU , Golding N , Pigott DM , Brady OJ , Moyes CL , Johansson MA , Gething PW , Velayudhan R , Khan K , Hay SI , Brownstein JS . Euro Surveill 2016 21 (20) Chikungunya fever is an acute febrile illness caused by the chikungunya virus (CHIKV), which is transmitted to humans by Aedes mosquitoes. Although chikungunya fever is rarely fatal, patients can experience debilitating symptoms that last from months to years. Here we comprehensively assess the global distribution of chikungunya and produce high-resolution maps, using an established modelling framework that combines a comprehensive occurrence database with bespoke environmental correlates, including up-to-date Aedes distribution maps. This enables estimation of the current total population-at-risk of CHIKV transmission and identification of areas where the virus may spread to in the future. We identified 94 countries with good evidence for current CHIKV presence and a set of countries in the New and Old World with potential for future CHIKV establishment, demonstrated by high environmental suitability for transmission and in some cases previous sporadic reports. Aedes aegypti presence was identified as one of the major contributing factors to CHIKV transmission but significant geographical heterogeneity exists. We estimated 1.3 billion people are living in areas at-risk of CHIKV transmission. These maps provide a baseline for identifying areas where prevention and control efforts should be prioritised and can be used to guide estimation of the global burden of CHIKV. |
Community-effectiveness of temephos for dengue vector control: a systematic literature review
George L , Lenhart A , Toledo J , Lazaro A , Han WW , Velayudhan R , Runge Ranzinger S , Horstick O . PLoS Negl Trop Dis 2015 9 (9) e0004006 The application of the organophosphate larvicide temephos to water storage containers is one of the most commonly employed dengue vector control methods. This systematic literature review is to the knowledge of the authors the first that aims to assess the community-effectiveness of temephos in controlling both vectors and dengue transmission when delivered either as a single intervention or in combination with other interventions. A comprehensive literature search of 6 databases was performed (PubMed, WHOLIS, GIFT, CDSR, EMBASE, Wiley), grey literature and cross references were also screened for relevant studies. Data were extracted and methodological quality of the studies was assessed independently by two reviewers. 27 studies were included in this systematic review (11 single intervention studies and 16 combined intervention studies). All 11 single intervention studies showed consistently that using temephos led to a reduction in entomological indices. Although 11 of the 16 combined intervention studies showed that temephos application together with other chemical vector control methods also reduced entomological indices, this was either not sustained over time or-as in the five remaining studies-failed to reduce the immature stages. The community-effectiveness of temephos was found to be dependent on factors such as quality of delivery, water turnover rate, type of water, and environmental factors such as organic debris, temperature and exposure to sunlight. Timing of temephos deployment and its need for reapplication, along with behavioural factors such as the reluctance of its application to drinking water, and operational aspects such as cost, supplies, time and labour were further limitations identified in this review. In conclusion, when applied as a single intervention, temephos was found to be effective at suppressing entomological indices, however, the same effect has not been observed when temephos was applied in combination with other interventions. There is no evidence to suggest that temephos use is associated with reductions in dengue transmission. |
Outbreaks of unexplained neurologic illness - Muzaffarpur, India, 2013-2014
Shrivastava A , Srikantiah P , Kumar A , Bhushan G , Goel K , Kumar S , Kumar T , Mohankumar R , Pandey R , Pathan P , Pappanna M , Pasi A , Pradhan A , Singh P , Somashekar D , Velayudhan A , Yadav R , Chhabra M , Mittal V , Khare S , Sejvar JJ , Dwivedi M , Laserson K , Earhart KC , Sivaperumal P , Kumar AR , Chakrabarti A , Thomas J , Schier J , Singh R , Singh RS , Dhariwal AC , Chauhan LS . MMWR Morb Mortal Wkly Rep 2015 64 (3) 49-53 Outbreaks of an unexplained acute neurologic illness affecting young children and associated with high case-fatality rates have been reported in the Muzaffarpur district of Bihar state in India since 1995. The outbreaks generally peak in June and decline weeks later with the onset of monsoon rains. There have been multiple epidemiologic and laboratory investigations of this syndrome, leading to a wide spectrum of proposed causes for the illness, including infectious encephalitis and exposure to pesticides. An association between illness and litchi fruit has been postulated because Muzaffarpur is a litchi fruit-producing region. To better characterize clinical and epidemiologic features of the illness that might suggest its cause and how it can be prevented, the Indian National Centre for Disease Control (NCDC) and CDC investigated outbreaks in 2013 and 2014. Clinical and laboratory findings in 2013 suggested a noninflammatory encephalopathy, possibly caused by a toxin. A common laboratory finding was low blood glucose (<70 mg/dL) on admission, a finding associated with a poorer outcome; 44% of all cases were fatal. An ongoing 2014 investigation has found no evidence of any infectious etiology and supports the possibility that exposure to a toxin might be the cause. The outbreak period coincides with the month-long litchi harvesting season in Muzaffarpur. Although a specific etiology has not yet been determined, the 2014 investigation has identified the illness as a hypoglycemic encephalopathy and confirmed the importance of ongoing laboratory evaluation of environmental toxins to identify a potential causative agent, including markers for methylenecyclopropylglycine (MCPG), a compound found in litchi seeds known to cause hypoglycemia in animal studies. Current public health recommendations are focused on reducing mortality by urging affected families to seek prompt medical care, and ensuring rapid assessment and correction of hypoglycemia in ill children. |
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