Journal Article

Successful experimental infant baboon model for childhood cryptosporidiosis studies

Nyariki, James Nyabuga, Nyachieo, Atunga, Chai, Daniel C., Jillani, Ngalla E.

2021

Overview

Background Cryptosporidiosis causes high morbidity and mortality in children under 2 years of age globally. The lack of an appropriate animal model that mimics the pathogenesis of disease in humans has hampered the development and testing of potential therapeutic options. This study aimed to develop and validate an infant baboon infection model of cryptosporidiosis. Methods Eighteen immunocompetent weaned infant baboons aged 12 to 16 months were used. The animals were n  = 3 controls and three experimental groups of n  = 5 animals each inoculated with Cryptosporidium parvum oocysts as follows: group 1: 2 × 10 4 , group 2: 2 × 10 5 , group 3: 2 × 10 6 followed by daily fecal sampling for oocyst evaluation. Blood sampling for immunological assay was done on the day of infection and weekly thereafter until the end of the experiment, followed by necropsy and histopathology. Statistical analysis was performed using R, SPSS, and GraphPad Prism software. Analysis of variance (ANOVA) and Bonferroni post hoc tests were used for comparison of the means, with p  < 0.05 considered as a significant difference. Correlation coefficient and probit analysis were also performed. Results In all experimental animals but not controls, the onset of oocyst shedding occurred between days 2 and 4, with the highest oocyst shedding occurring between days 6 and 28. Histological analysis revealed parasite establishment only in infected animals. Levels of cytokines (TNF-α, IFN-γ, and IL-10) increased significantly in experimental groups compared to controls. Conclusion For developing a reproducible infant baboon model, 2 × 10 4 oocysts were an effective minimum quantifiable experimental infection dose. Graphic abstract

• Publisher: BioMed Central,Springer Nature B.V,BMC
• Subject: Age Factors / analysis of variance / Animal models / Animals / Babies / Baboons / Biomedical and Life Sciences / Biomedicine / Blood / Childhood / Children / computer software / Correlation coefficient / Correlation coefficients / Cryptosporidiosis / Cryptosporidiosis - parasitology / Cryptosporidiosis - physiopathology / Cryptosporidium / Cryptosporidium parvum / Cryptosporidium parvum - growth & development / Cytokines / Disease Models, Animal / Dosage / Entomology / Experimental infection / Feces / Feces - parasitology / Female / histology / Histopathology / immunoassays / Immunocompetence / Immunology / Infant baboon / Infants / Infections / Infectious Diseases / Inoculation / Interleukin 10 / Laboratory animals / Male / Morbidity / mortality / Necropsy / Oocysts / Oocysts - pathogenicity / Papio / Parasite Egg Count / Parasites / Parasitology / Pathogenesis / Polymerase chain reaction / probit analysis / Protozoa and protozoan diseases / Sampling / Shedding / Statistical analysis / Statistical methods / Sucrose / therapeutics / Tropical Medicine / Tumor necrosis factor-α / Variance analysis / Veterinary Medicine/Veterinary Science / Virology / Weaning / Weekly / γ-Interferon