Molecular Diversity of Giardia duodenalis, Cryptosporidium spp., and Blastocystis sp. in Symptomatic and Asymptomatic Schoolchildren in Zambézia Province (Mozambique)

Abstract

Infections by the protist enteroparasites Giardia duodenalis, Cryptosporidium spp., and, to a much lesser extent, Blastocystis sp. are common causes of childhood diarrhoea in low-income countries. This molecular epidemiological study assesses the frequency and molecular diversity of these pathogens in faecal samples from asymptomatic schoolchildren (n = 807) and symptomatic children seeking medical attention (n = 286) in Zambézia province, Mozambique. Detection and molecular characterisation of pathogens was conducted by polymerase chain reaction (PCR)-based methods coupled with Sanger sequencing. Giardia duodenalis was the most prevalent enteric parasite found [41.7%, 95% confidence interval (CI): 38.8‒44.7%], followed by Blastocystis sp. (14.1%, 95% CI: 12.1‒16.3%), and Cryptosporidium spp. (1.6%, 95% CI: 0.9‒2.5%). Sequence analyses revealed the presence of assemblages A (7.0%, 3/43) and B (88.4%, 38/43) within G. duodenalis-positive children. Four Cryptosporidium species were detected, including C. hominis (30.8%; 4/13), C. parvum (30.8%, 4/13), C. felis (30.8%, 4/13), and C. viatorum (7.6%, 1/13). Four Blastocystis subtypes were also identified including ST1 (22.7%; 35/154), ST2 (22.7%; 35/154), ST3 (45.5%; 70/154), and ST4 (9.1%; 14/154). Most of the genotyped samples were from asymptomatic children. This is the first report of C. viatorum and Blastocystis ST4 in Mozambique. Molecular data indicate that anthropic and zoonotic transmission (the latter at an unknown rate) are important spread pathways of diarrhoea-causing pathogens in Mozambique.

Molecular Detection and Characterization of Intestinal and Blood Parasites in Wild Chimpanzees (Pan troglodytes verus) in Senegal

“…Remarkably, sequence data revealed that all ST1 isolates detected involved allele 8 and, to a much lesser extent, alleles 1 and 7. In contrast, human infections/colonisation by ST1 are primarily due to allele 4 in both developed or developing countries [ 72 , 73 ]. Taken together, this data suggests that different host-adapted genetic variants of ST1 are circulating in human and NHP populations.…”

An Update on Zoonotic Cryptosporidium Species and Genotypes in Humans

“…Cryptosporidium viatorum was originally reported in the UK in travellers returning from India and formally described as a human species in 2012 [ 73 ]. Since then, C. viatorum have been described in humans from Australia [ 66 ], China [ 114 ], Columbia [ 68 ], Ethiopia [ 34 , 64 , 74 ], India [ 63 , 67 ], Mozambique [ 62 ], Myanmar [ 65 ], Nigeria [ 69 , 70 ] and Swedish patients (who had returned from Kenya or Guatemala) [ 51 , 71 , 72 ]. It has also been detected in urban wastewater in China [ 204 ].…”

Molecular Detection of Soil-Transmitted Helminths and Enteric Protozoa Infection in Children and Its Association with Household Water and Sanitation in Manhiça District, Southern Mozambique

“…Certainly, this is a hospital-based cross-sectional study, thus, biases toward sick and symptomatic children. However, a cross-sectional study in Zambezia province, Mozambique, during 2017–2019 observed similar Giardia infection PCR detected prevalences in health centers and in schools in children between 3 and 14 years old (42% and 41.7%, respectively) [ 21 ]. Moreover, other studies in other Mozambican regions also showed Giardia infection among the most prevalent intestinal parasites.…”

“…and E. histolytica , were less prevalent in children attending healthcare in Manhiça district. Regarding Cryptosporidium spp , other hospital-based studies in Mozambique also detected prevalence below 6% by microscopy or PCR [ 21 , 24 ]. Nonetheless, Cryptosporidium spp .…”

“…Occasional studies have reported STH and S. stercoralis infections in Mozambique for decades [ 17 ], but current published data are scarce. Concerning enteric pathogens, although they were described in children under 5 [ 18 , 19 ], a small number of studies examined enteric protozoa infections in those over 5 years old in Mozambique [ 20 , 21 ].…”