title: Impact of MDA and the prospects of elimination of the lone focus of diurnally sub periodic lymphatic filariasis in Nicobar Islands, India.
abstract: Mass Drug Administration is being carried out in Andaman and Nicobar Islands, India since 2004. Cross sectional microfilaria (Mf) survey was conducted in Nancowry group of islands, the lone foci of diurnally sub periodic form of bancroftian filariasis in Nicobar district, to examine its eligibility for Transmission Assessment Survey (TAS). A total of 2561 individuals (coverage: 23.9%) were screened from five islands. The overall Mf prevalence was 3.28%. Except one island, all other islands recorded Mf prevalence >1%, ranging from 2.5% to 5.3%, indicating persistence of infection despite six annual rounds of MDA. Mf prevalence was age dependent and was higher among males, but not significantly different between genders. Age and gender specific analysis showed a significant reduction in all the age classes among females vis a vis pre-MDA prevalence while the reduction was significant only in 21-30 and 41-50 age classes in males. Exposure to day biting and forest dwelling Downsiomyia nivea can be attributed for the persistent infection besides non-compliance for MDA. Based on fits of modified negative binomial distribution, true prevalence of Mf carriers in the community was estimated to be 4.74%, which is markedly higher (about 24%) than the observed prevalence of 3.28%. Follow up of cohorts showed evidence of continued persistence of infection and acquisition of new infections post six rounds of MDA. As the Mf prevalence was above >1% in four of the five islands, this area is not eligible for TAS, warranting continuation of MDA. Mass DEC fortified salt is suggested as an adjunct to hasten elimination of infection.
authors.affiliation: Regional Medical Research Centre (Indian Council of Medical Research), Post Bag No. 13, Port Blair 744 101, Andaman & Nicobar Islands, India. Electronic address: shriraman@icmr.org.in.
authors.forename: A N
authors.initials: AN
authors.lastname: Shriram
authors.affiliation: Vector Control Research Centre (Indian Council of Medical Research), Medical Complex, Indira Nagar, Puducherry 605 014, India. Electronic address: kkrish_3@yahoo.com.
authors.forename: K
authors.initials: K
authors.lastname: Krishnamoorthy
authors.affiliation: Regional Medical Research Centre (Indian Council of Medical Research), Post Bag No. 13, Port Blair 744 101, Andaman & Nicobar Islands, India. Electronic address: arunsivan86@gmail.com.
authors.forename: Arun
authors.initials: A
authors.lastname: Sivan
authors.affiliation: Division of Malaria, Filaria & Vector Borne Diseases (National Vector Borne Diseases Control Programme), Directorate of Health Services, Andaman & Nicobar Administration, Port Blair 744 101, Andaman & Nicobar Islands, India. Electronic address: bpsahanvbdcp@gmail.com.
authors.forename: B P
authors.initials: BP
authors.lastname: Saha
authors.affiliation: National Institute for Research in Tuberculosis (earlier known as Tuberculosis Research Centre) (Indian Council of Medical Research), Mayor V Ramanathan Road, Chetpet, Chennai 600 031, India. Electronic address: kumaraswami@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Kumaraswami
authors.affiliation: Regional Medical Research Centre (Indian Council of Medical Research), Post Bag No. 13, Port Blair 744 101, Andaman & Nicobar Islands, India. Electronic address: vijayacharip@yahoo.com.
authors.forename: P
authors.initials: P
authors.lastname: Vijayachari
mesh_terms: D000293:Adolescent; D000328:Adult; D000330:Aedes / Q000254:growth & development; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D000871:Anthelmintics / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D003710:Demography; D060740:Disease Eradication / Q000379:methods*; D004358:Drug Therapy / Q000379:methods; D004605:Elephantiasis, Filarial / Q000188:drug therapy* / Q000453:epidemiology* / Q000517:prevention & control / Q000635:transmission; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D007303:Insect Vectors; D062312:Islands / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D055815:Young Adult
chemical_list: D000871:Anthelmintics
keywords: Elimination; India; Lymphatic filariasis; Sub periodic filariasis; Wuchereria bancrofti