Schistosome infections: an Indian perspective

Pleural schistosomiasis masquerading as tubercular pyopneumothorax: World's first case report

Schistosomiasis is an uncommon waterborne helminthic infection that infects humans. Although it is not prevalent in India, many cases are reported due to contact with infested water bodies. Schistosomiasis primarily involves the lower urinary tract and colorectal region. Pulmonary schistosomiasis, although very unusual, has been described with the systemic manifestation of the disease; however, pleural involvement with schistosomiasis has never been described before in the literature. We report this first case of pleural schistosomiasis masquerading as tuberculosis, which posed a diagnostic challenge and later a new learning point in the presentation of the disease.

Spectrum of parasitic infections in centrifuged urine sediments from a newly developed tertiary care centre in Central India

Detection of urinary parasites is relatively rare and incidental finding in routine urine examination. Common urinary parasitic infections as described in literature include Trichomonas, Schistosoma hematobium and Microfilaria. Trichomonas vaginalis is known to cause vaginitis and urethritis, and may be found in urine sediments. In this study, the spectrum of urinary parasitic infections that had been reported in the last one and a half year was evaluated, and point prevalence in this zone was estimated. Microbiologist opinion had been taken in the difficult cases. Out of the total centrifuged urine sediments examined, urinary parasitic infection was found in 33 cases. The calculated point prevalence is 0.39%. Most common parasitic infection reported was flagellates (27 cases: 25 T. vaginalis, 2 commensal flagellate closest to Chylomastix), followed by three cases showing eggs of Enterobius vermicularis, one case showing larvae of Strongyloides stercoralis and two cases of ciliate protozoa. One of the ciliate protozoa was Balantidium coli and the other one was Balantidium like ciliate morphologically closest to Chilodonella spp. Pyuria was found in 22 out of the 33 cases and hematuria in 17 out of 33 cases. A fairly wide morphological spectrum of parasites may be diagnosed through microscopic examination of centrifuged urine sediment. They may cause pyuria and haematuria, and morphological awareness helps in prompt and effective management in most cases.

Susceptibility of Snails to Infection with Schistosomes is influenced by Temperature and Expression of Heat Shock Proteins

The freshwater snail, Biomphalaria glabrata is the obligate intermediate host for the transmission of the parasitic trematode, Schistosoma mansoni the causative agent of the chronic debilitating neglected tropical disease, schistosomiasis. We showed previously that in juvenile snails, early and significant induction of stress manifested by the expression of stress proteins, Hsp 70, Hsp 90 and reverse transcriptase (RT) of the non- LTR retrotransposon, nimbus, is a characteristic feature of juvenile susceptible NMRI but not resistant BS-90 snails. These latter, however, could be rendered susceptible after mild heat shock at 32°C, revealing that resistance in the BS-90 resistant snail to schistosomes is a temperature dependent trait. Here we tested the hypothesis that maintenance of BS-90 resistant snails at the permissive temperature for several generations affects the resistance phenotype displayed at the non-permissive temperature of 25°C. The progeny of BS-90 snails bred and maintained through several generations (F1 to F4) at 32°C were susceptible to the schistosome infection when returned to room temperature, shedding cercariae at four weeks post-infection. Moreover, the study of expression levels of the heat shock protein (Hsp) 70 protein by ELISA and western blot analysis, showed that this protein is also differentially expressed between susceptible and resistant snails, with susceptible snails expressing more protein than their resistant counterparts after early exposure to wild-type but not to radiation-attenuated miracidia. These data suggested that in the face of global warming, the ability to sustain a reduction in schistosomiasis by using refractory snails as a strategy to block transmission of the disease might prove challenging since non-lethal elevation in temperature, affects snail susceptibility to S. mansoni.