Association between enteric protozoan parasites and gastrointestinal illness among HIV- and tuberculosis-infected individuals in the Chowke district, southern Mozambique

Abstract

Human immune deficiency virus (HIV) and tuberculosis (TB) infections remain major public health issues globally, particularly in sub-Saharan Africa. Impairment of both cell-mediated and humoral immunity by HIV and/or TB infections may limit the host’s defences against other pathogens, including the diarrheagenic protozoan Cryptosporidium spp., Giardia intestinalis, and Entamoeba histolytica. During September–December 2015 a cross-sectional study was conducted to assess the prevalence and molecular diversity of these enteric parasites among HIV- and/or TB-infected patients at a medical reference centre in Chowke district, southern Mozambique. A total of 99 stool specimens were initially screened by direct microscopy and further confirmed and characterised by molecular methods. DNA sequence analyses of the genes encoding the small subunit ribosomal RNA and the 60-kDa glycoprotein were used for the typing and sub-typing of Cryptosporidium isolates, respectively. G. intestinalis-positive isolates by real-time PCR were subsequently typed at the glutamate dehydrogenase locus. Differential diagnosis of E. histolytica/dispar was achieved by real-time PCR. G. intestinalis (8.1%) was the enteric protozoan more frequently detected, followed by Cryptosporidium spp. (7.1%), and Entamoeba histolytica/dispar (6.1%). Two HIV-infected (but not TB-infected) patients harbour G. intestinalis and Cryptosporidium spp. co-infections. Two (29%) G. intestinalis isolates were successfully characterised, revealing the presence of known AII and novel BIV genotypes. Four (57%) Cryptosporidium isolates were unmistakeable assigned to C. hominis, identifying two (IbA10G2 and IdA22) sub-types. Cryptosporidium infections were not associated to diarrhoea in HIV-positive patients, probably because improved immune function in the affected individuals due to antiretroviral therapy. G. intestinalis was considered a non-opportunistic pathogen, whereas the presence of E. histolytica could not be confirmed by molecular methods. Based on their common presence in the studied clinical population, we recommend the effective diagnosis and treatment of these enteropathogens for improving the management of HIV and TB patients.