Effects of long-term dehydration on stress markers, blood parameters, and tissue morphology in the dromedary camel (Camelus dromedarius).

Introduction: Dromedary camels robustly withstand dehydration, and the rough desert environment but the adaptation mechanisms are not well understood. One of these mechanisms is that the dromedary camel increases its body temperature to reduce the process of evaporative cooling during the hot weather. Stress in general, has deleterious effects in the body. In this study, we sought to determine the effects of dehydration and rehydration on stress parameters in the dromedary camels and how it pacifies these effects. Methods: Nineteen male camels were randomly divided into control, dehydrated and rehydrated groups, and fed alfalfa hay ad-libitum. The dehydrated and rehydrated groups were water-restricted for 20 days after which the rehydrated camels were provided with water for 72 h. The control and dehydrated camels were slaughtered at day 20 from the start of experiment whereas the rehydrated group was killed 72 h later. Many biochemical, hematological histopathological parameters and gene analysis were performed in relevant tissues collected including blood, plasma, and tissues. Results and discussion: It was observed that severely dehydrated camels lost body weight, passed very hard feces, few drops of concentrated urine, and were slightly stressed as reflected behaviorally by loss of appetite. Physiologically, the stress of dehydration elicited modulation of plasma stress hormones for water preservation and energy supply. Our results showed significant increase in cortisol, norepinephrine and dopamine, and significant decrease in epinephrine and serotonin. The significant increase in malondialdehyde was accompanied with significant increase in antioxidants (glutathione, retinol, thiamin, tocopherol) to provide tissue protection from oxidative stress. The physiological blood changes observed during dehydration serve different purposes and were quickly restored to normality by rehydration. The dehydrated/rehydrated camels showed reduced hump size and serous atrophy of perirenal and epicardial fat. The latter changes were accompanied by significantly increased expression of genes encoding proteins for energy production (ANGPTL4, ACSBG1) from fat and significantly decreased expression of genes (THRSP; FADS 1&2) encoding proteins enhancing energy expenditure. This process is vital for camel survival in the desert. Dehydration induced no major effects in the vital organs. Only minor degenerative changes were observed in hepatic and renal cells, physiological cardiomyocyte hypertrophy in heart and follicular hyperplasia in splenic but lipidosis was not depicted in liver hepatocytes. Ketone bodies were not smelled in urine, sweat and breathing of dehydrated animals supporting the previous finding that the ß hydroxybutyrate dehydrogenase, a key enzyme in ketone body formation, is low in the camel liver and rumen. Rehydration restored most of blood and tissues to normal or near normal. In conclusion, camels are adapted to combat dehydration stress and anorexia by increasing anti-stressors and modulating genes involved in fat metabolism.

More cell culture passaged Camelpox virus sequences found resembling those of vaccinia virus.

Background: Camelpox is the most infectious and economically important disease of camelids that causes significant morbidity and mortality rates. Several live attenuated vaccines against Camelpox virus (CMLV) are produced worldwide by passaging field isolates in cell culture. Sequence of a high passage Saudi isolate of CMLV was previously found closely resembled Vaccinia virus (VACV). Aim: To determine whether other high cell culture passage CMLV isolates are genetically resemble VACV and further to explore the possible mechanism of the resemblance. Methods: We performed polymerase chain reaction and DNA sequence analysis of A-type inclusion body protein (ATIP), L1R, and open reading frame (ORF) 185 genes on different cell culture passage levels of a field isolate, two high passage vaccines, wild-type, and reference strains of CMLV. Results: We demonstrate that additional two high passage attenuated vaccine candidate from Sudan and UAE likewise contain sequences resembling VACV more than CMLV. Furthermore, sequence analysis of the ATIP gene of selected virus passages in cell culture revealed that the shift to VACV-like occurred between passage 11 and 20 and up to the 10th passage the genome still resembles wild-type virus. This observation was further confirmed by recombination analysis which indicated recombination events at ATIP and ORF185 genes occurred at higher passages. Conclusion: We confirmed that the cell culture passage CMLV turns to resemble VACV after cell culture passage and concluded that the resemblance may not be a result of contamination or misidentification as previously thought but could be due to recombination events that occurred during the passage process.

Preliminary Comparative Assessment of Brucellergene Skin Test for Diagnosis of Brucellosis in Dromedary Camels (Camelus dromedarius).

This study was conducted to evaluate the use of Brucellergene skin test (BST) for the diagnosis of Brucellosis in camels (Camelus dromedarius) in comparison with Rose Bengal test (RBT) and competitive enzyme-linked immunosorbent assay (c-ELISA). A total of 68 apparently healthy adult dromedary camels of either gender from three different geographical locations of Abu Dhabi Emirate, United Arab Emirates (UAE), were included in the study. The skin test was applied on two shaved areas at the middle of the neck: one for the test and the other area was injected with normal saline as a control. Reading was done 72 h postinjection. Results were subjected to Bayesian analysis to assess the test performances in camels. The model estimated the following sensitivity and specificity median values: BST: Se = 70.72%, Sp = 98.82%; RBT: Se = 93.27%, Sp = 97.79%; and c-ELISA: Se = 94.78%, Sp = 98.48%. As the BST investigated in this study proved to be a highly specific test, we propose using it as a confirmatory test in camels particularly when the serological tests give doubtful results on individual animals.

Asymptomatic MERS-CoV Infection in Humans Possibly Linked to Infected Dromedaries Imported from Oman to United Arab Emirates, May 2015.

In May 2015 in United Arab Emirates, asymptomatic Middle East respiratory syndrome coronavirus infection was identified through active case finding in 2 men with exposure to infected dromedaries. Epidemiologic and virologic findings suggested zoonotic transmission. Genetic sequences for viruses from the men and camels were similar to those for viruses recently detected in other countries.

Prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels in Abu Dhabi Emirate, United Arab Emirates.

High seroprevalence of Middle East respiratory syndrome corona virus (MERS-CoV) in dromedary camels has been previously reported in United Arab Emirates (UAE). However, the molecular detection of the virus has never been reported before in UAE. Of the 7,803 nasal swabs tested in the epidemiological survey, MERS-CoV nucleic acid was detected by real-time PCR in a total of 126 (1.6 %) camels. Positive camels were detected at the borders with Saudi Arabia and Oman and in camels' slaughter houses. MERS-CoV partial sequences obtained from UAE camels were clustering with human- and camel-derived MERS-CoV sequences in the same geographic area. Results provide further evidence of MERS-CoV zoonosis.