Schistosomiasis at the Crossroad to Elimination: Review of Eclipsed Research with Emphasis on the Post-Transmission Agenda.

While chronic schistosomiasis is pathologically well defined, the acute form of the disease is less well understood. It is generally agreed that early lesions, such as lung nodules and bladder polyps, are reversible, which impedes identification of the time elapsed since exposure. The intermediate stage between the acute and the chronic forms of schistosomiasis requires further investigation, as does the clinical stage due to lesions remaining after treatment. With current schistosomiasis control efforts gradually progressing to elimination, there is a need to focus on post-transmission schistosomiasis, which not only refers to remaining lesions from previous infections, but also accounts for the potential presence of surviving worms after treatment. This issue is particularly salient for migrants from endemic to non-endemic countries and should be kept in mind for returning expatriates from schistosomiasis-endemic countries. Negative stool examination or urine filtration are generally taken as indicative of cure since rectoscopy for Schistosoma mansoni infection, or cystoscopy for S. haematobium infection, are rarely performed. However, pathology of affected organs may persist indefinitely, while potentially remaining live worms could produce additional pathology. Hence, post-transmission schistosomiasis can prevail for years after elimination of the disease, and thus, warrant further attention.

Intestinal parasites in segregated minority communities of Slovakia: results from a cross-sectional survey in children.

In Slovakia, the Roma population forms the second-largest ethnic minority. A large part of the Roma is semi-nomadic or lives in segregated settlements with poor living standards and limited access to health facilities. More than 40 years ago, a cross-sectional survey revealed a high prevalence of parasitic infections. There is a paucity of recent data, and hence, we designed a study to investigate the current status of intestinal parasitic infections in this population. Overall, 259 children aged 7 months to 18 years from 32 different segregated settlements provided faecal samples for microscopic examination using a sodium acetate-acetic acid-formalin concentration and the Paraprep L technique. Almost 40% of the samples yielded a positive result, with Ascaris lumbricoides (27.4%) and Giardia intestinalis (9.3%) being the most frequent helminth and intestinal protozoa species, respectively. Many children younger than 2 years were found to be infected, which suggests that community transmission is important. In view of our findings, there is a pressing need for targeted action to improve the health status of this neglected population.

Migration of the people and parasites: facts from survey of 5511 foreigners.

In the course of the years 1983-1989, 5511 foreigners in the age of 20 to 40 years old from 87 countries were examined for human parasites. Everyone was examined within 1 months of arrival in the Czech Republic in the Active Case Detection (ACD) program. The intensity of infection was measured in those parasites which do not reproduce in the human body. Intensity of infection with geohelmints was express as a number of eggs per gram of feaces (EPG). 1079 foreigners infected with Trichuris trichiura are in 94,8 % suffering of light infection, the cohort of 694 foreigners infected with Ascaris lumbricoides suffered in 49,8 % of light infection, and 349 individuals infected with hookworms suffer in 96,0 % of cases of light infection. Pathology of infection with Schistosoma is founded on immunopathological reaction of the capillary endothelium to antigen excreted by mature eggs resulting in granulomatous inflammation with more than 20 times higher synthesis of collagen type I. Restructuralized tissue of liver, urinary bladder and large intestine with fibrotic scar, persisted 26 months though parasite was cured. 50 individuals from African countries were positive for infection with Plasmodium falciparum. 37/74, % of those were asymptomatic carriers with parasite load less than 10 000 merozoits per 1 µl of peripheric blood. That is the threshold between asymptomatic carrier and carries of the disease. All 37 Africans claimed absence of the disease before departure to the Czech Republic. The presence of RBC in trophozoit of Entamoeba histolytica is undoubtedly related to their virulence. In stool of 235 patients suffering for diarrhea in Cambodian hospital only 11,6 % of them harboured motile trophozoits of Entamoeba histolytica with phagocyte RBC confirming amoebic etiology of diarrhea. Such proportion of pathogenic amoeba is accepted all around the world. Keywords: Foreigners, imported parasites, active case detection, passive case detection, intensity of infection, clinical course of infection, cured parasite, persisting pathology.

Impact of antifibrotic treatment on the course of Schistosoma mansoni infection in murime model

Administration of an antifibrotic agent as an adjunct to antihelmintic treatment with the objective of morbidity reduction was investigated in the nurine schistosomiasis mansoni model. Antifibrotic, ß-aminopropionitrile treatment has a profound effect on the cellular composition of the liver granuloma of Schistosoma mansoni infected mice when given alone, resulting in increase macrophage infiltration. These macrophages, in response to stimulation with soluble egg antigen or lipopolysaccharide produced elevated levels of nitric oxide but low levels of tumor necrosis factor alpha compared to untreated infected mice. This also correlated with reduced liver granuloma size. In spite of low numbers of eggs in the liver, mice receiving a combine treatment had a high level of resistance to a challenge infection compared with mice receiving only praziquantel. Those mice also exhibited a reduced lymphocyte proliferative response, similar to that of infected untreated mice. Antifibrotic treatment has an impact on the dynamic of the cellular nature of granulomas and impacts on the host immunity to infection.