ABSTRACT
BACKGROUND & OBJECTIVES: Lymphatic filariasis (LF) is endemic in the state of Assam and mass drug administration (MDA) programme for LF elimination is being implemented in the state since 2004. A study on prevalence of microfilaria (mf), disease endemicity and vector infection was carried out in a tea garden population of Dibrugarh, Assam (India) to assess the effect of ongoing MDA programme on elimination of LF. METHODS: Finger prick thick blood smears (20 mm3) were made from individuals aged ≥2 yr old during night blood survey in between 2000-0000 hrs during the period of November 2012 to February 2013. Blood smears were dehaemoglobinised, stained with Giemsa and examined under microscope for presence of mf. Indoor resting mosquitoes were collected during 0600-1000 hrs and female Culex quinquefasciatus were dissected and examined under microscope for larval forms of the parasite. RESULTS: A total of 634 blood smears were collected and screened for mf and 47 (7.41%) individuals were found microfilaraemic, with predominance of males (74.5%). Highest mf rate (20.0%) was seen in the males of 30-39 yr age group while in females, age group of 10-19 yr recorded maximum mf rate (5.48%). Entomological collection and dissection of Cx. quinquefasciatus revealed presence of larval stages of the parasite and infection and infectivity rates recorded were 13.20 and 3.70%, respectively. Chronic clinical manifestations in the form of elephantiasis and hydrocele were recorded in 33 (5.73%) subjects of the 575 examined. INTERPRETATION & CONCLUSION: Mass drug administration data showed six rounds of MDA with drug distribution coverage in between 63.42 and 95.93% in the study population. Out of 634 individuals examined 47 were found microfilaraemic giving an overall infection rate of 7.41%. Mosquito vector infection and infectivity rates were 13.20 and 3.70%, respectively. Presence of high mf rate, vector infectivity rate and clinical cases in the study population after six rounds of MDA warrants concerted efforts to be made for effective implementation and monitoring of MDA for success of LF elimination programme.
Subject(s)
Elephantiasis, Filarial/drug therapy , Filaricides/administration & dosage , Adolescent , Adult , Animals , Child , Culex/parasitology , Elephantiasis, Filarial/epidemiology , Elephantiasis, Filarial/parasitology , Elephantiasis, Filarial/transmission , Female , Humans , India/epidemiology , Insect Vectors/parasitology , Male , Middle Aged , Prevalence , Tea/growth & development , Wuchereria bancrofti/drug effects , Wuchereria bancrofti/growth & development , Wuchereria bancrofti/isolation & purification , Young AdultSubject(s)
Elephantiasis, Filarial/epidemiology , Adolescent , Adult , Age Factors , Aged , Child , Child, Preschool , Female , Humans , India/epidemiology , Infant , Infant, Newborn , Insect Proteins , Male , Middle Aged , Sex Factors , SilkABSTRACT
Current status of bancroftian filariasis among two distinct communities of Upper Assam was evaluated. High prevalence (10.3% mf rate) in tea workers descendents of tribals migrated from endemic states such as Orissa, Bengal, Uttar Pradesh and southern states of India, were recorded. Among non tea workers (indigenous population) significantly low mf rate was found in spite of the fact that both the communities are living in close vicinity and in similar ecological and mosquitogenic conditions. Culex quinquefasciatus was incriminated as vector in the areas of both the communities. A group of recent migrants of Bihar and Bengal living in the locality of non tea worker population were also found microfilaraemic. Significantly lower infection rate in non tea worker population appears to be associated with host susceptibility to the infection. Familial clustering in microfilaraemic subjects noticed in tea workers group also suggests involvement of racial susceptibility to infection.
Subject(s)
Elephantiasis, Filarial/epidemiology , Adolescent , Adult , Child , Child, Preschool , Female , Humans , India/epidemiology , Industry , Infant , Male , Middle Aged , Prevalence , TeaSubject(s)
Filariasis/epidemiology , Wuchereria bancrofti/isolation & purification , Adolescent , Adult , Animals , Child , Child, Preschool , Female , Humans , India/epidemiology , Industry , Infant , Male , Middle Aged , Prevalence , TeaABSTRACT
Follow up of microfilaraemic individuals infected with Wuchereria bancrofti at five years after treatment was carried out in a tea workers population. Diethylcarbamazine citrate in the dose schedule of 72 mg/kg body weight given in equal daily doses over a period of 21 days cleared 51.6 per cent microfilaraemic individuals five year post-treatment. Eighty five subjects were successfully followed and among these, 10 (11.8%) showed increase in mf counts, 31 (36.4%) showed reduction but remained microfilaraemic and 44 (51.8%) became amicrofilaraemic. The age and sex of the host had no significant effect on the clearance of mf. Persistence of a relatively stable low number of mf in treated individuals is more likely due to survival of one or more female worms after the therapy or due to reinfection which could not be ruled out in the present study. Overall, findings indicated that diethylcarbamazine citrate appeared to give a long-term benefit to treated individuals.
