Equine Histoplasmosis in Ethiopia: Phylogenetic Analysis by Sequencing of the Internal Transcribed Spacer Region of rRNA Genes.

Equine histoplasmosis commonly known as epizootic lymphangitis (EL) is a neglected granulomatous disease of equine that is endemic to Ethiopia. It is caused by Histoplasma capsulatum variety farciminosum, a dimorphic fungus that is closely related to H. capsulatum variety capsulatum. The objective of this study was to undertake a phylogenetic analysis of H. capsulatum isolated from EL cases of horses in central Ethiopia and evaluate their relationship with H. capsulatum isolates in other countries and/or clades using the internal transcribed spacer (ITS) region of rRNA genes. Clinical and mycological examinations, DNA extraction, polymerase chain reaction (PCR), Sanger sequencing, and phylogenetic analysis were used for undertaking this study. Additionally, sequence data of Histoplasma isolates were retrieved from GenBank and included for a comprehensive phylogenetic analysis. A total of 390 horses were screened for EL and 97 were positive clinically while H. capsulatum was isolated from 60 horses and further confirmed with PCR, of which 54 were sequenced. BLAST analysis of these 54 isolates identified 29 H. capsulatum isolates and 14 isolates from other fungal genera while the remaining 11 samples were deemed insufficient for further downstream analysis. The phylogenetic analysis identified five clades, namely, African, Eurasian, North American 1 and 2, and Latin American A and B. The Ethiopian isolates were closely aggregated with isolates of the Latin American A and Eurasian clades, whereas being distantly related to isolates from North American 1 and 2 clades as well as Latin American B clade. This study highlights the possible origins and transmission routes of Histoplasmosis in Ethiopia.

Epidemiology of Epizootic Lymphangitis Among Carthorses in Ethiopia.

Epizootic lymphangitis caused by Histoplasma capsulatum variety farciminosum is a debilitating disease incurring considerable economic losses and affecting the welfare of carthorses. Understanding of its epidemiology is important for devising effective prevention and control measures. A cross-sectional study was conducted on 4,162 carthorses in 17 towns in Ethiopia between October 2018 and June 2019. Clinical and microscopic examinations, fungal culturing, and polymerase chain reaction were used to undertake this study. The overall prevalence of epizootic lymphangitis was 16.67% (95% CI: 15.55-17.84) in carthorses. Epizootic lymphangitis was detected in carthorses found in 16 of the 17 towns included in the study. The highest prevalence was recorded at Kombolcha Town (33.33; 95% CI: 27.54-39.52) whereas the lowest was recorded at Debre Birhan Town (0.00; 95% CI: 0.00-1.27). The results of univariable firth logistic regression analysis showed that the difference between the prevalence of Kombolcha and the prevalences of all the other towns except Holota and Shashemene were statistically significant. Statistically significantly lower prevalence was observed in other towns. Classification of the cases into different clinical forms showed that 87.18, 4.33, and 0.58% were cutaneous, ocular, and respiratory forms respectively, while the remaining 7.93% (55/694; 95% CI: 6.03-10.19) were classified as mixed form. In terms of the severity of the disease, 28.67, 60.52, and 0.81% were mild, moderate, and severe cases, respectively. The majority of the lesions (43.95%) were observed in the skin followed by forelimbs (14.55%) and neck region (14.27%). Higher mean annual temperature, lower annual rainfall, and higher humidity of the study towns were statistically significantly associated with an increased risk of epizootic lymphangitis. In conclusion this study revealed widespread occurrence of epizootic lymphangitis in carthorses yet a heterogeneous prevalence between towns. The veterinary and livestock authorities should take this into account while devising disease control.

Obesity and STING1 genotype associate with 23-valent pneumococcal vaccination efficacy.

BACKGROUNDObesity has been associated with attenuated vaccine responses and an increased risk of contracting pneumococcal pneumonia, but no study to our knowledge has assessed the impact of obesity and genetics on 23-valent pneumococcal vaccine (PPSV23) efficacy. We assessed the relationship of obesity (primary analysis) and stimulator of interferon genes (STING1) genotype (secondary analysis) on PPSV23 efficacy.METHODSNonobese (BMI 22-25 kg/m2) and obese participants (BMI ≥30 kg/m2) were given a single dose of PPSV23. Blood was drawn immediately prior to and 4-6 weeks after vaccination. Serum samples were used to assess PPSV23-specific antibodies. STING1 genotypes were identified using PCR on DNA extracted from peripheral blood samples.RESULTSForty-six participants were categorized as nonobese (n = 23; 56.5% women; mean BMI 23.3 kg/m2) or obese (n = 23; 65.2% women; mean BMI 36.3 kg/m2). Obese participants had an elevated fold change in vaccine-specific responses compared with nonobese participants (P < 0.0001). The WT STING1 group (R232/R232) had a significantly higher PPSV23 response than individuals with a single copy of HAQ-STING1 regardless of BMI (P = 0.0025). When WT was assessed alone, obese participants had a higher fold serotype-specific response compared with nonobese participants (P < 0.0001), but no difference was observed between obese and nonobese individuals with 1 HAQ allele (P = 0.693).CONCLUSIONSThese observations demonstrate a positive association between obesity and PPSV23 efficacy specifically in participants with the WT STING1 genotype.TRIAL REGISTRATIONClinicalTrials.gov NCT02471014.FUNDINGThis research was supported by the NIH and the University of Florida MD-PhD Training Program.

Population Structure and Genomic Breed Composition in an Angus-Brahman Crossbred Cattle Population.

Crossbreeding is a common strategy used in tropical and subtropical regions to enhance beef production, and having accurate knowledge of breed composition is essential for the success of a crossbreeding program. Although pedigree records have been traditionally used to obtain the breed composition of crossbred cattle, the accuracy of pedigree-based breed composition can be reduced by inaccurate and/or incomplete records and Mendelian sampling. Breed composition estimation from genomic data has multiple advantages including higher accuracy without being affected by missing, incomplete, or inaccurate records and the ability to be used as independent authentication of breed in breed-labeled beef products. The present study was conducted with 676 Angus-Brahman crossbred cattle with genotype and pedigree information to evaluate the feasibility and accuracy of using genomic data to determine breed composition. We used genomic data in parametric and non-parametric methods to detect population structure due to differences in breed composition while accounting for the confounding effect of close familial relationships. By applying principal component analysis (PCA) and the maximum likelihood method of ADMIXTURE to genomic data, it was possible to successfully characterize population structure resulting from heterogeneous breed ancestry, while accounting for close familial relationships. PCA results offered additional insight into the different hierarchies of genetic variation structuring. The first principal component was strongly correlated with Angus-Brahman proportions, and the second represented variation within animals that have a relatively more extended Brangus lineage-indicating the presence of a distinct pattern of genetic variation in these cattle. Although there was strong agreement between breed proportions estimated from pedigree and genetic information, there were significant discrepancies between these two methods for certain animals. This was most likely due to inaccuracies in the pedigree-based estimation of breed composition, which supported the case for using genomic information to complement and/or replace pedigree information when estimating breed composition. Comparison with a supervised analysis where purebreds are used as the training set suggest that accurate predictions can be achieved even in the absence of purebred population information.