The National Academy of Vectors and Vector Borne Diseases in India: two decades of progress.

The National Academy of Vector Borne Diseases (NAVBD) was founded at Bhubaneswar in 1994, by Dr AP Dash, along with 15 like-minded scientists from all over India. NAVBD is a non-profit academic organization in India, dedicated to advancing and promoting knowledge on vectors and vector-borne diseases, and encouraging scientists and members of the academy to conduct research on vectors and vector-borne diseases. NAVBD convenes national and international seminars, symposia and workshops to exchange knowledge on recent advances in the field of vectors and vector-borne diseases and raise public awareness. Plans are under way to expand the Academy’s activities to the rest of the South- East Asia Region.

Precontrol observations on lymphatic filariasis & geo-helminthiases in two coastal districts of rural Orrisa.

BACKGROUND & OBJECTIVE: Lymphatic filariasis (LF) is a major public health problem in India, accounting for 40 per cent of the global burden. The World Health Organization has launched a global programme to eliminate LF by 2020 and India is a signatory to it. Orissa, an eastern Indian State has long been known to be endemic for LF. Prior to implementation of mass drug administration programme it is important to collect baseline data on filariasis and geo-helminthiases in the State. The present cross-sectional survey was therefore carried out between February and December 2001 to obtain baseline information on both LF and geo-helminthiases before application of the control measures. METHODS: The study was carried out in rural areas of Puri and Ganjam districts in two phases. In phase I, the distribution of microfilaraemia in two district was mapped out in randomly selected primary health centres (PHCs), and 12 microfilaraemic villages were identified in each district by cluster analysis for the phase II study. In phase II, detailed clinical and parasitological survey for LF and geo-helminthiases was carried out following the standard procedures. RESULTS: Wuchereria bancrofti was found to be widely prevalent in Puri district with certain pockets of Brugia malayi while W. bancrofti was the only species in Ganjam district. The microfilaraemia (Mf) rate was found to be 9.5 and 11.1 per cent; and circulating filarial antigenaemia (CFA) was 16.8 and 17.8 per cent in Puri and Ganjam respectively. The geometric mean intensity (GMI) of Mf per ml of blood among positive individuals was 387 in Puri and 454 in Ganjam. The overall disease rate in Puri was 7.9 and 8.9 per cent in Ganjam. The prevalence of chronic manifestations was found to be significantly higher (P<0.001) than the acute manifestations in both the districts. The prevalence of geo-helminthiases was 31.8 per cent in Puri and 42.1 per cent in Ganjam; and the heavy infection was found to be significantly higher (P<0.001) in Ganjam compared to Puri district. INTERPRETATION & CONCLUSION: The present study identified LF and geo-helminthiases as widely distributed health problem in rural areas of coastal Orissa which warrants intervention measures along the lines recommended by the global programme for elimination of LF and geo-helminthiases to reduce the disease burden.

A clinico-epidemiological perspective of lymphatic filariasis in Satyabadi block of Puri district, Orissa.

BACKGROUND & OBJECTIVES: Lymphatic filariasis is a major public health problem in the coastal district of Orissa. However, no systematic studies have been done to document the prevalence of microfilaraemia/disease in different regions of the State. Therefore, the present cross sectional study was undertaken during 1996-97 to obtain information on the clinical and epidemiological status of the disease in Satyabadi block area of Puri district, known to be endemic for filariasis. METHODS: Night blood smear survey and clinical examinations were performed on 4646 individuals aged 0-> or = 60 yr from systematically selected households of 17 randomly selected villages of the Block. Microfilaraemia was detected by thick drop technique using 20 microliters of peripheral blood and microfilariae (mf) density by nucleopore filtration technique collected during 1900-2300 h. RESULTS: The prevalence of microfilaraemia was observed to be 14.8 per cent; 13.3 per cent Wuchereria bancrofti, 1.4 per cent Brugia malayi and 0.09 per cent had mixed infections. Geometric mean microfilaraemia density (infected persons only) was found to be 1288 per ml in case of W. bancrofti and 204 per ml in case of B. malayi. The disease rate was observed to be 19.8 per cent; 12.85 per cent had acute manifestations and 6.97 per cent had chronic manifestations. INTERPRETATION & CONCLUSION: The rate of acute disease manifestations was observed to be significantly higher (P < 0.001) than chronic manifestations. There was a male preponderence among the affected individuals (P < 0.001). The interesting observations of the study were the occurrence of occult filarial manifestations viz., tropical pulmonary eosinophilia (TPE) in 0.47 per cent cases and other associated manifestations like asymptomatic microscopic haematuria, monoarticular arthritis and filarial associated respiratory diseases in 0.50, 0.24 and 0.19 per cent of cases respectively. The present study indicates that the area is highly endemic for lymphatic filariasis with active transmission.

Occurrence of asymptomatic microscopic haematuria in a filarial endemic area of Orissa, India.

To determine the frequency of occurrence of asymptomatic microscopic haematuria in filarial endemic area of Orissa, where the mf rate and disease rate were observed to be 14.8% and 37.2% respectively, clinical examination, night blood smear examination, morning midstream urine examination were conducted on 697 persons-randomly selected from all age groups in 8 villages of Puri tehsil. Out of them, 15.6% were found to have asymptomatic haematuria (Grade I-14.7%, Grade II-0.6%, Grade-III 0.3%). The prevalence of asymptomatic microscopic haematuria was observed to have positive statistical correlation with mf status (P < 0.001), filarial antigenaemia (Ag) (P < 0.001), antibody (Ab) (P < 0.001) and circulating immunocomplex antigen (CIC-Ag) (P < 0.001). The prevalence was also found to be increased with the progression of the disease process i.e. from endemic normal to chronic manifestations. None of the cases having Grade-II and III haematuria cases revealed any gross renal pathological lesions, when subjected to special investigations like X-ray, IVP, cystoscopy and urethroscopy.

Evaluation of cyfluthrin and fenfluthrin for their insecticidal activity against three vector mosquitoes.

The EC50/EC90 concentrations of cyfluthrin and fenfluthrin were tested for their activity against different developmental stages of three important vector mosquitoes viz., Anopheles stephensi Liston, Aedes aegypti (Linn.) and Culex quinquefasciatus Say. The EC90 concentrations of both cyfluthrin and fenfluthrin showed ovicidal effect on An. Stephensi and Ae. aegypti whereas EC90 of cyfluthrin checked the hatching of eggs completely in Cx. quinquefasciatus. Fenfluthrin at EC50 concentration reduced the percentage of hatching significantly (p < 0.05) only in An. stephensi. Both the compounds were more active against the fourth larval instars of all mosquito species and cyfluthrin in culicines (17.3% Ae. aegypti = 9.1%) and fenfluthrin in anophenlines (An. stephensi = 36.8%) brought about maximum inhibition in adult emergence. Various types/degrees of morphogenetic aberrations were induced in all mosquito species on treatment with these compounds. Cyfluthrin treated female mosquitoes showed reduced fecundity rates in An. stephensi (p < 0.05), Cx. quinquefasciatus (p < 0.001) and fenfluthrin treated in An. stephensi (p < 0.5) and Ae. aegypti (p < 0.05). The fertility rates of all the mosquito species were significantly reduced (p < 0.001) by both the compounds.

Prevalence of G-6-PD deficiency in a malaria endemic tribal area of Orissa (India).

A total of 207 men belonging to Bhuyan, Juanga and Munda tribes and 108 non-tribal residents of Banspal block area of Keonjhar district of Orissa were screened for glucose-6-phosphate dehydrogenase (G-6-PD) deficiency, abnormal haemoglobin and malaria parasite. In the tribal group, G-6-PD enzyme deficiency was observed in 13.52 per cent as compared to 3.70 per cent in non-tribals. No abnormal haemoglobin was detected in the studied population, while 15.87 per cent of individuals were positive for Plasmodium falciparum. An extremely weak association was observed between malaria and G-6-PD deficiency.

Effect of drug treatment on the prevalence of intestinal parasites amongst school children in a sub-urban community.

The prevalence of intestinal protozoal and helminthic infection was studied over a period of one year amongst 297 school children, aged 5-20 yr in a sub-urban area. The overall prevalence rate of various protozoal infection, 15.82 per cent had only helminthic infection and 14.47 per cent had combined helminthic and protozoal infection. Ascaris lumbricoides infestation was found to be the commonest helminthic infection (61.70%) while giardiasis was the commonest protozoal infection (59.80%). The prevalence rates, one year after effective anti-protozoal and antihelminthic treatment was administered, were overall parasitic infection 25.92 per cent; only protozoal infection 17.50 per cent, only helminthic infection 5.72 per cent and combined infection 2.69 per cent. The reinfection rate was found to be 7.40 per cent and the fresh infection rate was found to be 11.4 and 39.8 per cent at the end of six months and one year respectively.