Declining prevalence of pulmonary paragonimiasis following treatment & community education in a remote tribal population of Arunachal Pradesh, India

Background & objectives: In India, human pulmonary paragonimiasis is an important public health problem in the northeastern (NE) region. In 2005 we reported a hyperendemic focus of paragonimiasis in a remote tribal village in the hills of Changlang district in Arunachal Pradesh. The community was made aware of the disease and all active cases were treated. This study was aimed to assess the decline in the prevelance of paragonimiasis in the same area after a re-survey done in 2011 after a gap of six years. Methods: Re-surveys were carried to determine the reduction in the prevalence of paragonimiasis. Community education was given to the villagers to raise their awareness about paragonimiasis. A total of 624 individuals including 301 children (age < 15 yr) were included in the study. Sputum and stool samples were examined for eggs of lung flukes. Serum samples were screened for IgG antibodies against lung fluke antigen by ELISA. Results: A significant (P<0.001) decline in the prevalence of paragonimiasis was found. There was decline in both ELISA positivity and egg positivity. Antibody positivity against excretory-secretary (ES) antigen in children (age < 15 yr) fell down from earlier 51.7 to 15.9 per cent and in individuals 16 - 30 yr of age the serological prevalence fell down from 22.4 to 8.2 per cent and in individuals aged > 31 yr, the decline in prevalence was from 15.3 to 3.7 per cent. Gender-wise analysis revealed that the decline in ELISA positivity was similar in both genders and fell down from 33.9 to 11.5 per cent in males and from 29.8 to 10.7 per cent in females. Similarly, there was a significant decline rate in egg positivity also. Interpretation & conclusions: The strategy of hotspot targeted active paragonimiasis case detection and treatment of infected cases together with community education appears to be feasible methods to achieve control of paragonimiasis in this region.

Cure and reinfection patterns of geohelminthic infections after treatment in communities inhabiting the tropical rainforest of Assam, India.

Mass de-worming targeted at socio-economically poor communities can be considered as an option for communities living in the tropical forests of Assam who do not have access to safe drinking water and proper sanitation, and consequently have a higher risk of suffering from geohelminthic infection and associated morbidity. A random sample of 265 subjects was included in this study (134 males and 131 females). The chemotherapeutic regimen followed was a single dose of albendazole 400 mg. Stools samples were collected in 10% formol-saline for detection of infection before treatment. Post-treatment stool samples were collected 10 to 14 days after treatment to determine the cure rate. Stool samples were again collected 3 to 6 months post-treatment to study the rate of reinfection. Multiple logistic regression was used to find possible associations between age, sex and treatment failure. The chi-square test was used wherever appropriate. The cure rates for Ascaris lumbricoides, Trichuris trichiura and hookworms were 70.8%, 68.7% and 93.0%, respectively. Logistic regression revealed that age was associated with treatment failure in A. lumbricoides infection. Re-infection rates after 3 months of successful treatment were 19.6% for A. lumbricoides, 30.9% for T. trichiura and 11.3% for hookworms. Six months post-treatment, the prevalence of re-infection was highest with T. trichiura (43.6%); followed by A. lumbricoides (35.3%). The rate of reinfection with hookworms was lower (11.3%) six months post-treatment. The rates of re-infection with A. lumbricoides and T. trichiura was higher in children below 15 years of age, compared with adults. Hookworm reinfection was higher in the adult age group (15 to 39 years). The rates of new infection in previously uninfected subjects were lower compared with the rates for re-infection.

Prevalence of Trichuris trichiura in relation to socio-economic & behavioural determinants of exposure to infection in rural Assam.

BACKGROUND & OBJECTIVES: Stunting, anaemia, and the poor level of mental development are known to be associated with Trichuris trichiura infections. However, no information is available on the socio-environmental predictors relevant to Trichuris infection in rural communities. Whilst geohelminthic infections per se is an inevitable consequence of poor personal hygiene and household sanitation, the importance of specific factors in the epidemiology of Trichuris infection have not been formally investigated. The objective of this study was to explore, quantify and study different socio-environmental risk factors and find out their possible interaction vis-a-vis T. trichiura infection. METHODS: The study population consisted of 244 children (aged 15 yr and below) and 336 adults selected from 144 randomly selected households belonging to three villages of upper Assam. The prevalence rate ratio (PRR; = relative risk) and 95 per cent confidence interval (CI) were calculated. Univariate, multivariate analysis using Cox's proportional hazards regression assuming constant risk period and a tree-based risk factor analysis, were used. RESULTS: In the overall multivariate model, open field defaecation, large family size, and three or more children in the household were found independently associated with Trichuris infection. Gender specific analysis revealed that in females the age was also independently associated with increased risk of infection whereas in males, earth flooring was the most significant risk factor independently associated with the risk of Trichuris infection. Tree-based risk factor analysis indicated interaction between defaecating habits of people and the source of drinking water. INTERPRETATION & CONCLUSIONS: Installation of pit latrines (if not sanitary latrines) together with provision for safe drinking water and the construction of cement floors would probably reduce community prevalence of T. trichiura effectively.

Incrimination of Schistosoma spindale as a causative agent of farmer's dermatitis in Assam with a note on liver pathology in mice.

Cercarial dermatitis of paddy field workers in Assam is very common. However, it is not known which species of animal schistosomes, is its causative agent in Assam. Studies in two dermatitis affected villages of Dibrugarh district revealed that cercariae of Schistosoma spindale were involved in its aetiology. Indoplanorbis exustus was the only snail species found infected with apharyngeate brevifurcate schistosome cercarie. Experimental infection of the laboratory animals with the dermatitis causing schistosome cercariae revealed that duckling and chicken were refractory to infection. However, Swiss albino mice were successfully infected. The number of adult flukes per infected mice ranged from 6-321 (mean intensity = 68.1; S.D. = +/- 112.96). Histopathological study of infected mice liver revealed that there was mild inflammation of infected portal triads towards the presence of male flukes in the intra hepatic portal vessels. Kuppffer cells showed hyperplasia and contained large amounts of black pigment. No eggs or egg granulomas were detected in the liver parenchyma. There was no evidence of thrombophlebitis, septal fibrosis or pipe stem fibrosis.

Human distomatosis due to Fasciola hepatica infection in Assam, India.

A seven year old girl in a rural area of Upper Assam was found to be infected with Fasciola hepatica. The girl gave history of eating watercress. Besides the presence of eggs in the stools, her liver was enlarged and tender. Liver function tests revealed hepato-biliary involvement with increase in serum AKP and ALT. Ultrasonography revealed presence of adult fluke in gall bladder, and a marginal thickening of gall bladder wall. However, the echo pattern of her liver parenchyma was normal. The case is reported for its public health significance and is a maiden report from north eastern India.