INTESTINAL PARASITES IN TWO RURAL COMMUNITIES LIVING IN THE CORDILLERAPROVINCE (PLURINATIONAL STATE OF BOLIVIA)

INTRODUCTION: In last years sanitary conditions of people living in Bolivia improved with more extended access to safe drinking water and sanitation (Eder et al., 2012, Rev Panam Salud Publica, 32:43-8). However, the situation is still suboptimal in some communities and undetermined in others. The research here reported, which is part of a complete parasitological screening, was aimed at collecting data about intestinal parasites affecting people of two rural communities: Bartolo and Ivamirapinta (SE Bolivia). MATERIALS AND METHODS: In 2013, a total of 220 faecal samples were collected and submitted to microscopic examination (directly and after Ridley concentration). Parasites were identified on the basis of their morphological features. Samples positive to Entamoeba histolytica complex and to Blastocystis were further analysed to identify the species/subtype (ST) involved in each infection. DNA was extracted and amplified (Nested-PCR and PCR followed by sequencing, respectively) following the described protocols (Solaymani et al., 2006, J Clin Microbiol, 44: 2258-61; Bohm-Gloning et al., 1997, Trop Med Int Health, 2: 771-8). RESULTS: In Bartolo, the overall infection rate was 81.2% (91/112), and the most commonly found protozoan was Blastocystis spp. (43.7%), followed by Entamoeba coli (37.5%), Entamoeba hartmanni (17.9%), Giardia intestinalis (14.3%), Iodamoeba butschlii (10.8%), Endolimax nana (8%), Chilomastix mesnili (8%), and E. histolytica complex (7.1%). Helminth eggs identified belonged to Hymenolepis nana (8%), Ascaris lumbricoides (3.6%) and hookworms (1.8%). In Ivamirapinta, infection figure was 79.7% (86/108), and the most commonly found protozoan was Blastocystis (60.2%), followed by E. hartmanni (36.1%), E. coli (25%), E. histolytica complex (13%), E. nana (11.1%), I. butschlii (10.2%), G. intestinalis (10.2%), C. mesnilii (2.8%). Moreover, H. nana (2.8%) and Strongyloides stercoralis (0.9%) were found. In Bartolo and in Ivamirapinta multiple infections amounted to 51.8% and 53.7%, respectively, and the second community proved significantly more affected by Blastocystis and E. hartmanni (P=0,02 and P=0.037, respectively). Most of the protozoa detected were scarcely pathogenic, however E. histolytica was identified in 6 subjects in the first community and in 8 people in Ivamirapinta. As for Blastocystis, in Bartolo were found ST1 (n=4) and ST3 (n=1), whereas in the other community also ST2 (n=2), beside ST1 (n=4) and ST3 (n=2), was identified. CONCLUSIONS: Being H. nana the most prevalent helminth found, the contamination with human fresh faeces is frequent in both communities. This finding contrasts with the almost absence of human geohelminths, probably consequence of the implemented program of preventive chemotherapy. Zoonotic opportunistic species like Balantidium coli and Cryptosporidium are not present, but most protozoa found in the presented study, G. intestinalis included, are anthropo-zooparasites that have pigs or dogs as possible additional sources of infection, therefore health educational programs should be improved.