Intestinal parasites in Northern India: effects of climate patterns on prevalence of different intestinal parasites in children

During the course of the project (2013-2016), PhD-student Kjersti Selstad Utaaker (KSU) has had 6 research stays in Chandigarh, India with primary focus on sample collection. Overall, she has collected in over 1000 samples of selected types (water, vegetables, and animal faecal samples) in order to investigate the potential sources and vehicles of transmission of parasites, particularly Cryptosporidium and Giardia, to children. Samples were analysed using both microscopy and molecular methods, and lab experiments were also undertaken to evaluate survival of parasite transmission stages (Cryptosporidium oocysts, Giardia cysts) on fresh produce. In order to reduce the expense of analysis, modifications of the ISO Methods for analysis of water and fresh produce for contamination were developed and evaluated during the course of this work. The results of some of these studies are already published, but other are still under evaluation at different journals or in preparation. Furthermore, some of the results have been presented in both oral and poster format at different meetings, including the final stakeholders? meeting of the project that was held in Chandigarh in February 2017. KSU?s PhD thesis resulting from these studies is planned for submission during summer 2017. The most relevant findings resulting from the Norway-responsible studies within the project include: ANIMAL STUDIES 1) Although Giardia is common in dogs in Chandigarh, the majority are not zoonotic and are thus an unlikely source of human infection. Other potentially zoonotic parasites identified in dog faeces from parks in Chandigarh included Toxocara eggs and Strongyle-type eggs, assumed to be Ancylostoma caninum (manuscript in preparation). 2) Cryptosporidium parvum was identified in cattle samples and was of the same sub-type as those reported from humans in Chandigarh, but the prevalence was relative low; the majority of Giardia isolates from cattle samples were not zoonotic. Thus, although these parasites in cattle may contribute to the burden of human infection, they seem unlikely to be a major source (manuscript in preparation). 3) Zoonotic Giardia were identified in around 30 % of 207 goat (beetal) samples. This is an unexpected finding and may indicate more common exchange of these parasites between backyard goats in India and their human owners than noted from other regions of the world; however, Cryptosporidium infection was relatively low prevalence in the goat samples, although this may reflect that largely adult goats were sampled (manuscript submitted). 4) A study conducted as part of the ?sister? ZooPa project (funded by SIU) indicated that zoonotic Giardia occurred in over 30 % of 170 monkey samples (rhesus macaque) collected from and around Chandigarh (article published). WATER & VEGETABLE STUDIES 1) The modified methods for sample analysis provided reliable and robust data (recovery efficiencies of around 30-50% in independent lab trials), at a fraction of the cost of the equivalent ISO Methods (article published). 2) Analysis of 71 10-litre samples of potable water supplies from in and around Chandigarh, found that they were rather likely to be contaminated with Cryptosporidium oocysts and/or Giardia cysts (over 20 % of treated water samples positive). The more wealthy areas of the city seemed less likely to receive water contaminated with protozoan parasites than other areas. Generally, concentrations of parasites in water samples were low, although one sample from a slum area contained large numbers of Giardia cysts. Although fluctuations in the prevalence and concentrations of parasites in the water samples related to season (monsoon season or not) were not detected, this could reflect the unusual climatic conditions during sampling (article submitted). 3) Fresh produce (284 samples analysed) was less likely to be contaminated with Cryptosporidium oocysts and/or Giardia cysts than drinking water (11 % of samples positive), and levels of contamination tended to be low. Nevertheless, some of these parasites were shown to be zoonotic. Interestingly, food from supermarkets seemed no less likely to be contaminated than fresh produce bought from market stalls, and the levels of Cryptosporidium oocysts were higher on fresh produce from supermarkets than elsewhere, perhaps reflecting customer handling practices (article submitted). 4) Although both Cryptosporidium oocysts and Giardia cysts survived on refrigerated fresh produce, Cryptosporidium oocysts were also sufficiently robust to survive for several days (up to 2 weeks) at room temperature (article published). In conclusion, it seems that both drinking water and fresh produce may be relevant infection vehicles of intestinal parasites in Chandigarh. Although both monkeys and goats may relevant sources of Giardia cysts that may infect humans, our data suggest that human-to-human spread, either directly or via water or food, may be of greater importance.

In order to achieve these objectives, the project plan has been divided into 4 different Work Packages (WP), of which 3 are concerned with the research questions to be addressed (WP1 - Disease & infection with intestinal parasites in children in Chandigar h; WP2 - Parasites on fresh produce and in water, and their potential as transmission vehicles; WP3 - Effect of regional and large-scale climate patterns on the occurrence of intestinal parasites and the construction of epidemiological models of these dis eases in Chandigarh). The 4th WP involves project management and dissemination issues. The 3 research-directed WP are inter-related, providing information and data that feeds into each other, and each of the partners has particular specialist expertise re lating to one WP. Each of the research-directed WP, provide input to WP4, which is concerned with dissemination. Thus our consortium provides a synergistic approach to addressing an important question regarding parasitic infection, transmission, local env ironment and climate.