Survey of Candidate Single-Nucleotide Polymorphisms in SLC11A1, TLR4, NOD2, PGLYRP1, and IFNγ in Ankole Longhorn Cattle in Central Region of Uganda to Determine Their Role in Mycobacterium avium Subspecies paratuberculosis Infection Outcome.

Julius Boniface Okuni,Lonzy Ojok,Mathias Afayoa

doi:10.3389/fvets.2021.614518

Julius Boniface Okuni, Lonzy Ojok + Show 1 more

Open Access

https://doi.org/10.3389/fvets.2021.614518

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Abstract

Mycobacterium avium ssp. paratuberculosis (MAP) is the cause of Johne's disease (JD) in a wide range of domestic and wild ruminants. Single-nucleotide polymorphisms (SNPs) in several genes including solute-like carrier 11A1 (SLC11A1), interferon gamma (IFNγ), Toll-like receptor 4 (TLR4), nucleotide-binding oligomerization domain 2 gene (NOD2), and bovine peptidoglycan recognition protein 1 (PGLYRP1) have been implicated in influencing the infection outcome of MAP in cattle. We have carried out a survey in a population of Ankole cattle from three districts in the central region of Uganda including Isingiro, Lyantonde, and Rakai to determine the role played by several SNPs on the above genes in the infection outcome of local cattle in Uganda. Nine hundred fifty-five heads of cattle obtained from 93 herds were tested using ELISA. Thirty-five ELISA-positive cattle and 35 negative herd mates from a total of 955 cattle tested for MAP were genotyped using iPLEX MassARRAY genotyping systems to detect the presence of a total of 13 SNPS in five different genes (SLC11A1, IFNγ, TLR4, NOD2, and PGLYRP1). The cow-level prevalence of MAP infection in Ankole Longhorn cattle in the three districts was 3.98% (35/955), while the herd-level prevalence was 27.9% and within-herd prevalence was 12 ± 1.5% (95% CI = 9.1–14.8%). The genotypes and allele frequencies of the MAP-positive cattle were compared with those of their ELISA-negative herd mates to determine the significance of the polymorphisms. The results showed that SNPs rs109915208, rs110514940, and rs110905610 on SLC11A1, c.480G>A and c.625C>A on PGLYRP1, and c.2021C>T on TLR4 were monomorphic in both seropositive and seronegative cattle and therefore had no influence on the infection outcome. The remaining SNPs studied in the five genes [SLC11A1: rs109614179; TLR4: rs29017188 (c.226G>C), c.2021C>T; NOD2: rs110536091, rs111009394; PGLYRP1: c.102G>C, c.480G>A, c.625C>A; IFNγ: rs110853455] were polymorphic, but their allele and genotype frequencies did not show any significant difference between the seropositive and seronegative cattle. No significant difference was observed for any haplotype at the gene level.

Highlights

Mycobacterium avium ssp. paratuberculosis (MAP) is the cause of paratuberculosis (PTB) or Johne’s disease (JD), a chronic granulomatous enteritis characterized by projectile watery diarrhea in cattle, marked weight loss, submandibular edema, and eventual death [1]
This study was done with the aim of determining the effect of selected single-nucleotide polymorphisms (SNPs) on the seropositivity of Ankole Longhorn cattle to M. avium ssp. paratuberculosis in central Uganda
The findings indicate that the prevalence of MAP infection in Ankole cattle is within the same range as it has been reported in mixed breed study in other districts within the central region of Uganda

Summary

Introduction

Mycobacterium avium ssp. paratuberculosis (MAP) is the cause of paratuberculosis (PTB) or Johne’s disease (JD), a chronic granulomatous enteritis characterized by projectile watery diarrhea in cattle (or loose feces in other species), marked weight loss, submandibular edema, and eventual death [1]. PTB causes serious economic loses to the dairy industry in developed countries [2], and it is becoming increasingly relevant in Africa as well [3] Economic impacts of this disease stem from poor growth rate, progressive weight loss, reduced milk production, increased culling, death in affected animals, and loss of market for replacement heifers from affected farms [4]. The biggest risk factor for any herd or population of susceptible cattle is the presence of a clinically affected animal that is shedding the causative agent In such herds, infected cattle shed MAP through colostrum, milk, and feces and are ingested through feeding of milk or contaminated pasture and water [5]. The other challenge is that culling is extremely expensive and could practically shut down some farms with no guarantee that the MAP-free stock to be introduced will not get infected, since it takes a long time to get rid of MAP from the farm environment [8]

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