DNA methylation networks underlying mammalian traits

Using DNA methylation profiles (n = 15,456) from 348 mammalian species, we constructed phyloepigenetic trees that bear marked similarities to traditional phylogenetic ones. Using unsupervised clustering across all samples, we identified 55 distinct cytosine modules, of which 30 are related to traits such as maximum life span, adult weight, age, sex, and human mortality risk. Maximum life span is associated with methylation levels in HOXL subclass homeobox genes and developmental processes and is potentially regulated by pluripotency transcription factors. The methylation state of some modules responds to perturbations such as caloric restriction, ablation of growth hormone receptors, consumption of high-fat diets, and expression of Yamanaka factors. This study reveals an intertwined evolution of the genome and epigenome that mediates the biological characteristics and traits of different mammalian species.

Molecular detection and characterization of Theileria sp. from hedgehogs (Paraechinus aethiopicus) in Saudi Arabia

In this study, we conducted molecular detection and characterization of piroplasms that infect the Ethiopian or desert hedgehogs (Paraechinus aethiopicus) in Saudi Arabia. Blood samples from 112 (68 males and 44 females) desert hedgehogs from Unaizah, Central Saudi Arabia were screened for Theileria/Babesia DNA using the polymerase chain reaction (PCR) employing specific primers amplifying the partial 18S small subunit rRNA gene. Theileria DNA was detected in 51 samples (45·5%), giving a prevalence of 45·5%. Theileria DNA was found in 33 (48·5%) males and 18 (40·9%) females, and there was no significant difference (P > 0·05) in the prevalence between males and females. Similarly, there was no significant difference (P > 0·05) in the prevalence between juveniles (40%) and adults (46·7%). There was a significant difference in the prevalence of Theileria in hedgehogs collected from May to September and the period from October to April (P = 0·003). Four haplotypes of Theileria sp. in hedgehogs were detected and designated as H1-H4. H1 was the predominant haplotype and found in 80·8% of the positive individuals. Partial sequences of the 18S rRNA of Theileria sp. from hedgehogs grouped with Theileria spp. that are benign. This study is the first report of the occurrence of Theileria spp. in Saudi Arabian desert hedgehogs.

Cross-sectional prevalence study of MERS-CoV in local and imported dromedary camels in Saudi Arabia, 2016-2018

The Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) is an endemic virus in dromedaries. Annually, Saudi Arabia imports thousands of camels from the Horn of Africa, yet the epidemiology of MERS-CoV in these animals is largely unknown. Here, MERS-CoV prevalence was compared in imported African camels and their local counterparts. A total of 1399 paired sera and nasal swabs were collected from camels between 2016 and 2018. Imported animals from Sudan (n = 829) and Djibouti (n = 328) were sampled on incoming ships at Jeddah Islamic seaport before unloading, and local camels were sampled from Jeddah (n = 242). Samples were screened for neutralizing antibodies (nAbs) and MERS-CoV viral RNA. The overall seroprevalence was 92.7% and RNA detection rate was 17.2%. Imported camels had higher seroprevalence compared to resident herds (93.8% vs 87.6%, p <0.01) in contrast to RNA detection (13.3% vs 35.5%, p <0.0001). Seroprevalence significantly increased with age (p<0.0001) and viral RNA detection rate was ~2-folds higher in camels <2-year-old compared to older animals. RNA detection was higher in males verses females (24.3% vs 12.6%, p<0.0001) but seroprevalence was similar. Concurrent positivity for viral RNA and nAbs was found in >87% of the RNA positive animals, increased with age and was sex-dependent. Importantly, reduced viral RNA load was positively correlated with nAb titers. Our data confirm the widespread of MERS-CoV in imported and domestic camels in Saudi Arabia and highlight the need for continuous active surveillance and better prevention measures. Further studies are also warranted to understand camels correlates of protection for proper vaccine development.

A comparative morphological and histological study of the gastrointestinal tract of four insectivorous bat species: Asellia tridens, Chaerephon pumilus, Nycteris thebaica, Rhinopoma hardwickii

Various studies address the morphology of the gastrointestinal tracts (GITs) of insectivorous bat species. However, detailed morphometric studies including mucin histochemistry are scarce. This study compares various GIT measurements as well as the quantification of intestinal mucin secreting cells in four insectivorous bat species representing four different families of Chiroptera. Alcian blue/Periodic acid Schiff's stain was used to differentiate between acid and neutral mucin-secreting cells while the Aldehyde fuchsin/Alcian blue stain further differentiated between two acid mucins, namely sialo-, and sulphomucins. The number of cells was quantified and statistically analysed. All species had a simple GIT morphology represented by a simple, completely glandular stomach and the absence of a cecum. The exception was R. hardwickii, where a small cecum was observed which had histological mucosal features of both the small and large intestine. In R.hardwickii, distal to the cecum, typical colonic mucosal features such as the absence of villi and an abundance of goblet cells were observed. In all four species, the total number of goblet cells increased from the proximal to the distal intestinal regions. Mixed (acid and neutral) mucins dominated the entire GIT of all species. Neutral mucin-secreting cells were observed in the gastric pylorus and proximal intestinal regions in all species. Brunner's glands stained positive for neutral mucins. Exclusively acid mucin-secreting cells were seen in the distal intestinal regions of all species except N. thebaica. Sulphomucin-secreting cells were the most prominent acid mucin cell-type towards the distal intestine. The distribution of different mucin secreting cells indirectly provides information regarding the quality of the intestinal biofilm in the species studied.

Waterpipe smoking as a public health risk: Potential risk for transmission of MERS-CoV

The Middle East Respiratory Syndrome (MERS-CoV) emerged in the Kingdom of Saudi Arabia in 2012 causing a critical challenge to public health. The epidemiology of MERS-CoV remain enigmatic as human-to-human transmission is not fully understood. One possible scenario that might play a role in the virus transmission is the cultural waterpipe smoking. Cafés providing waterpipe smoking in cities within Saudi Arabia have been moved to areas outside city limits that frequently place them close to camels markets. We report results of a surveillance study wherein waterpipe hoses throughout several regions in Saudi Arabia were tested for the presence of MERS-CoV. A total of 2489 waterpipe samples were collected from cities where MERS-CoV cases were continuously recorded. MERS-CoV RNA wasn’t detected in collected samples. Irrespective of the negative results of our survey, the public health risk of waterpipe smoking should not be underestimated. To avoid a possible transmission within country where MERS-CoV is prevalent, we recommend the replacement of resusable hoses with “one-time-use” hoses in addition to a close inspection of waterpipe components to assure the appropriate cleaning and sanitization.