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Updated: May 31, 2025
Studying Cryptosporidium Infection in 3D Tissue-derived Human Organoid Culture Systems by Microinjection
Published on: September 14, 2019
Risk Factors and Circulating Subtypes of Cryptosporidium spp. and Giardia duodenalis in Hospitalized Children in
Ofélia Nhambirre1,2, Maria Luísa Lobo1,3,4, Idalécia Cossa-Moiane2,5
1Unidade de Parasitologia Médica, Grupo de Parasitas Oportunistas/VIH e Outros Parasitas, Global Health and Tropical Medicine, GHTM, Associate Laboratory in Translation and Innovation Towards Global Health, LA-REAL, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, 1349-008 Lisboa, Portugal.
Insights
Cryptosporidium and Giardia duodenalis infections in Mozambican children are linked to location and mother's education. Molecular analysis revealed Cryptosporidium hominis dominance and anthroponotic transmission for both parasites.
Area of Science:
- Infectious Diseases
- Molecular Epidemiology
- Public Health
Background:
- Cryptosporidium spp. and Giardia duodenalis are significant causes of childhood diarrhea in developing nations.
- Limited understanding of the molecular epidemiology of these parasites hinders effective control strategies.
- Mozambique faces a substantial burden of diarrheal diseases in children.
Purpose of the Study:
- To investigate the risk factors associated with Cryptosporidium and Giardia duodenalis infections in children with diarrhea in Mozambique.
- To determine the genetic diversity of Cryptosporidium spp. and Giardia duodenalis using molecular methods.
- To elucidate the transmission routes of these protozoan parasites in the study population.
Main Methods:
- Nested PCR assays targeting the ssu rRNA and gp60 genes for Cryptosporidium spp. and the b-giardin gene for G. duodenalis.
- Collection of sociodemographic and clinical data through questionnaires.
- Analysis of genetic subtypes and assemblages for both parasites.
Main Results:
- Significant risk factors for Cryptosporidium infection included location, mother's education level, and child's age. Cryptosporidium hominis was the predominant species (77.8%), with subtype Ib being most common.
- Risk factors for Giardia duodenalis infection included location, consumption of untreated water, and living in masonry houses. Assemblage A (predominantly AII) was dominant.
- The prevalence of specific subtypes (IbA9G3 for C. hominis) and subassemblages (AII for G. duodenalis) suggests a predominantly anthroponotic transmission route.
Conclusions:
- Location, maternal education, and age are key risk factors for Cryptosporidium infection in Mozambican children.
- Environmental factors like untreated water and housing type are associated with Giardia duodenalis infection.
- The molecular data strongly indicate that anthroponotic transmission is the primary route for both Cryptosporidium and Giardia duodenalis in this setting, highlighting the importance of human-to-human or human-to-environment transmission pathways.
Abstract:
Cryptosporidium spp. and Giardia duodenalis are important diarrheal agents in children in developing countries. Little is known about their molecular epidemiology; as such, the objective of this study was to determine the risk factors and genetic diversity of both parasites in diarrheal samples in Mozambique. In this study, two nested PCRs targeting ssurRNA and gp60 genes were used for genetic diversity of Cryptosporidium spp. and b-giardin for G. duodenalis. Sociodemographic and clinical characteristics were obtained through questionnaires. The location (odds ratio [OR] 3.499), mother's education level (OR 2.150) and age were significant factors for acquiring infection by Cryptosporidium spp. (p < 0.05). Cryptosporidium hominis was the predominant (77.8%) species. Four families (three C. hominis and one C. parvum) were identified, with the highest for Ib (73.9%), followed by Id (13%), Ia (8.7%) and IIc (4.3%). The location (p-value < 0.001), drinking untreated water (p-value = 0.04) and living in masonry houses (p-value = 0.002) were identified as risks associated with G. duodenalis infection. Assemblage A was the dominant type (65.2%). Among the subassemblages of assemblage A, AII was the most frequent (86.6%), followed by AIII (6.6%). For assemblage B, subassemblages BIII (87.5%) and BIV (12.5%) were identified. The dominance of the subtype IbA9G3 of C. hominis, as well as the AII subassemblage of G. duodenalis, seems to indicate that the transmission of both protozoa occurs mainly through the anthroponotic route.
