Factors influencing the prevalence of subclinical mastitis in lactating dromedary camels in Riyadh Region, Saudi Arabia

Toll like receptor 4 (TLR4) gene polymorphism and its association with somatic cell score and milk production traits in Indian dromedary camels

Our study aimed to explore the genetic variation in the Toll-like receptor 4 (TLR4) gene and establish its association with somatic cell score (SCS) and milk production traits in four Indian camel breeds namely Bikaneri, Kachchhi, Jaisalmeri and Mewari. TLR4 gene fragment of 573 bp spanning 5' UTR, exon-1 and partial intron-1 region was amplified and genotyped using the PCR-sequence based typing method. Only one SNP located at position C472T was identified. Genotyping revealed two alleles (C and T) and three genotypes: CC, CT and TT. The genotype frequencies for CC, CT and TT were 0.116, 0.326 and 0.558 and allele frequencies for C and T alleles were 0.279 and 0.721, respectively. Association study inferred that the effect of genotype on SCS, lactation yield (LY) and peak yield (PY) was non-significant however heterozygote (CT) genotypes recorded lower SCS and higher LY and PY. It can be concluded that the TLR4 gene possesses limited genetic variation, depicting polymorphism at a single locus in Indian camel breeds with a predominance of the TT genotype. The association study indicated that heterozygote animals possess better udder health and production performance, the statistical significance of which needs to be established using a large data set.

Camels' biological fluids contained nanobodies: promising avenue in cancer therapy

Cancer is a major health concern and accounts for one of the main causes of death worldwide. Innovative strategies are needed to aid in the diagnosis and treatment of different types of cancers. Recently, there has been an evolving interest in utilizing nanobodies of camel origin as therapeutic tools against cancer. Nanotechnology uses nanobodies an emerging attractive field that provides promises to researchers in advancing different scientific sectors including medicine and oncology. Nanobodies are characteristically small-sized biologics featured with the ability for deep tissue penetration and dissemination and harbour high stability at high pH and temperatures. The current review highlights the potential use of nanobodies that are naturally secreted in camels’ biological fluids, both milk and urine, in the development of nanotechnology-based therapy for treating different typesQuery of cancers and other diseases. Moreover, the role of nano proteomics in the invention of novel therapeutic agents specifically used for cancer intervention is also illustrated.

Risk factors associated with subclinical mastitis and its effect on physico-mineral features of camel milk

This study was carried out to determine the risk factors implicated in camel subclinical mastitis as well as the physico-mineral features of camel milk, there by examining the effect of this disease on those parameters. Milk samples were obtained from 125 lactating multiparous she-camels (aged 10-12 years) during early lactation from December 2020 to April 2021. The samples were screened for the presence of subclinical mastitis using the somatic cell count (SCC) test. In total, 73 (58.4%) samples showed the presence of subclinical mastitis, whereas the remaining 52 (41.6%) samples showed negative results for subclinical mastitis. Standard methods were used to appreciate the pH and mineral composition of the milk samples, such as Ca, Na, Cl, and K contents. In camels, unhygienic udder condition was identified as the major risk factor for the incidence of subclinical mastitis. Calf mortality and increased herd size were associated with a higher prevalence of subclinical mastitis. Tick infestations were also significantly associated with increased disease risk. Use of antisuckling devices, increase in milk yield, and weakness of body condition were identified as main risk factors and were primarily associated with the disease. However, udder lesions and deformities, milking frequency, and owner visits had no significant influence on the occurrence of subclinical mastitis. The overall mean pH value was 6.54 ± 0.01 and the mean values of Ca, Na, Cl, and K contents were 148.24 ± 2.55, 53.83 ± 1.52, 124.99 ± 1.80, and 240.22 ± 3.80 mg/100 g, respectively. When the level of milk from healthy animals and that from camels with subclinical mastitis (SCC > 2.4 × 10⁵) were compared, it showed that Na and Cl contents were significantly increased (p < 0.05) with the increase in SCC (56.52 vs.50.07 and 128.26 vs.120.40 mg/100 g, respectively). In contrast, there were no notable changes (p > 0.05) in the Ca, K, and pH values. In conclusion, udder hygiene, calf mortality, herd size, tick infestations, use of antisuckling devices, higher milk yield, and body condition were identified as the major risk factors that predispose the camels to subclinical mastitis. Furthermore, an increase in the Na and Cl levels in camel milk was observed along with udder inflammation. Consequently, the elevated Na and Cl levels in milk can be a sign of subclinical mastitis in camels.

Pathological insights into camel mastitis

Camel is a multipurpose animal bred to produce milk, meat, and transport and serves as a financial reserve for pastoralists by playing an important role in social prestige and prosperity. Camel milk is a good substitute for human milk because of its exceptional nutritional properties. Udder infections are considered one of the main limitations to camel farming. In recent decades, the disease has been reported by numerous camel-producing countries in Africa and Asia, such as Egypt, Somalia, Sudan, Kenya, Saudi Arabia, and Iraq. The current review provides an overview of the forms of camel mastitis, which can be clinical mastitis characterized by hardening and swelling of the breast, pain on palpation, and visible changes in the colour and texture of the milk or subclinical mastitis refers to the presence of inflammation with no obvious signs and it can be detected by indirect tests such as the California mastitis test (CMT), somatic cell count (SCC), and microbiological examination. Major pathogens of camel mastitis are Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli, and Corynebacterium bovis. Regarding the risk factors for camel mastitis, this study provides an overview of the most important risk factors such as severe tick infestation, teat injuries, hygienic milking protocols, and physiological disorders causing mastitis. The use of indirect tests and bacteriological studies as diagnostic tools and their values for detecting camel mastitis will also be reviewed. Based on the above, further epidemiological studies on camel mastitis are needed to have solid scientific data on disease transmission, pathogen characterization, other possible risk factors or diagnostic methods, and the impact of the disease on public health. Proper control strategies should be adopted through early diagnosis, treatment and by avoiding potential risk factors to get good quality milk from camels.

Macroscopic anatomy, radiography and computed tomography of normal paranasal sinuses of the adult one-humped dromedary (Camelus dromedarius)

In order to improve the current knowledge of the topography and the anatomy of the paranasal sinuses of the one‐humped dromedary (Camelus dromedarius), we applied both conventional and advanced imaging techniques, namely, radiography and computed tomography (CT). Twelve heads of healthy dromedaries were used; eight heads were dissected to obtain skulls for the fenestration of the sinuses, two heads underwent anatomical sections, and two heads were imaged respectively by radiography and CT. Sinus fenestration allowed observation of sinuses and their communications. In each dissected dromedary's head, the frontal sinus is a large compartment delimited by thick partitions. The sphenoid sinus is divided into small compartments by bony plates. The lacrimal sinus occupies a small cavity in the rostro‐medial lacrimal bone of the orbit. In all dissected heads, there was neither palatal sinus nor ventral conchal sinus. Five images obtained by CT were selected with an excellent correspondence with the anatomical sections. These images allowed a good differentiation between bones and sinus cavities. The visualisation of the sinus cavities and their anatomical limits has better quality using the CT compared to the radiography. Radiographic and CT images are therefore very useful for the interpretation of clinical imaging studies of the dromedary's paranasal sinuses.

Review of milk let-down in camels and proposition of a milk recording method

The aim of this article was to review the milk let-down in camels and to propose a simple milk recording method. Milking of camels generally starts between 1 and 3 months postpartum. The udder is stimulated for 0.5 to 2 min by either calf suckling or hand massaging to induce the milk let-down. About 40% of daily milk yield is consumed by the calf before and after milking. The best interval between milking is 8-12 h. Lactation length is in the range 8-18 months, and the mean total milk yield is 1000-4000 kg. Peak yield of 4 to 10 kg is attained between 2 and 7 months post calving, and persistency is greater than 85%. The proposed milk recording method for camels has been adapted from ICAR's procedures. The milking (manual or machine) starts after a suckling period of 1 month. Before each milking, the udder is stimulated for 1 min, either by calf suckling or by hand massaging. The milk recording interval is 36 days. The first test recording must take place within 75 days following the end of the suckling period. Milk yield recorded is the milk off-take or milked only. The lactation period corresponds to the milking length. Records are standardized to the reference lactation of 335 days. At each recording day, milk yields are recorded and milk samples are collected alternatively at either morning or evening milking. It was concluded that using this method, a sound milk recording database will be built for camels.

Subclinical mastitis in pastoralist dairy camel herds in Isiolo, Kenya: Prevalence, risk factors, and antimicrobial susceptibility

Mastitis is an important constraint to milk production in pastoralist camel (Camelus dromedarius) herds in Kenya. The objective of this study was to investigate the prevalence, risk factors, and bacterial panorama of subclinical mastitis (SCM) in pastoralist camel herds in Isiolo County, Kenya. Furthermore, antimicrobial susceptibility in udder pathogens was studied. A cross-sectional sample of 206 camels from 20 milking herds was screened using the California Mastitis Test (CMT), and quarter milk was subjected to bacterial culturing. Isolates were confirmed using MALDI-TOF mass spectrometry analysis, and antimicrobial susceptibility was determined using the broth microdilution method. Interviews focusing on herd management were conducted with camel owners. Subclinical mastitis, defined as a CMT score ≥ 3 (scale 1 to 5) and absence of clinical symptoms in the udder, were present in all visited herds. On the individual level, 46% of the camels had at least 1 quarter affected with SCM, and on the quarter level the prevalence was 26%. Intramammary infections (IMI) were common; out of 798 quarter milk samples, 33% yielded conclusive bacterial growth. The sensitivity and specificity of CMT for correctly identifying quarters with IMI were 82% and 92%, respectively. The most prevalent pathogen was Streptococcus agalactiae (72% of IMI-positive quarters), followed by non-aureus staphylococci (19%) and Staphylococcus aureus (13%). Antimicrobial susceptibility testing revealed that only a low proportion (4.9%) of Strep. agalactiae isolates was sensitive to tetracycline. For Staph. aureus, 59.1% of isolates exhibited sensitivity to penicillin. Skin lesions on the teats or udder were a risk factor for SCM. Increased age, parity, and stage of lactation were associated with increased risk of both SCM and IMI. Older camels with a blind teat or a previous history of mastitis were more likely to be infected with Strep. agalactiae. Hygiene routines for milking were largely absent in the observed herds, and knowledge of adequate milk handling was limited. The poor udder health is likely to depend on multiple factors, most prominently the within-herd maintenance of contagious udder pathogens, in combination with difficult sanitary conditions and lack of awareness among camel keepers. This study showed that in pastoralist camel herds around Isiolo town, SCM and IMI specifically caused by Strep. agalactiae are common udder health problems and are associated with increasing age, parity, and stage of lactation, and skin lesions on the teats and udder. Resistance to tetracycline in Strep. agalactiae was common. Control strategies specifically targeting SCM and adapted to pastorally managed camel herds need to be developed to reduce disease, combat antimicrobial resistance, and improve the livelihoods of pastoralists.

The CD markers of camel (Camelus dromedarius) milk cells during mastitis: the LPAM-1 expression is an indication of possible mucosal nature of the cellular trafficking

Studying the cellular populations of the camel mammary glands through the expression pattern of the CD markers and adhesion molecules is a mean to define whether the cellular trafficking pathway is peripheral or mucosal nature. Camel milk cells from 8 Gram-positive and 5 Gram-negative infected camels were examined with flow cytometry using cross-reacting antibodies like, anti-CD4(+), CD8(+), WC+1(+)γδ, CD62L, CD11a(+)/CD18, LPAM-1, CXCR2. The overall results indicated high flow cytometry output of most of the CD makers. The statistical analysis of the mean percentage of the expressed CD markers has shown that CD62L, CXCR-2, LPAM-1, CD11a/CD18, CD8(+), IL-6R and CD20(+) were expressed in significant differences in either type of the infection. The LPAM-1 expression has provided further support to the notion that the lymphocyte trafficking is of the mucosal nature. The mucosal origin of cellular trafficking has important implications on the vaccine design and therapeutical approaches to mastitis.

Feasibility of utilising an infrared-thermographic technique for early detection of subclinical mastitis in dairy camels (Camelus dromedarius)

Despite the proven ability of infrared thermography (IRT) technology for early detection of subclinical mastitis in dairy cows/sheep/goats, studies on its diagnostic feasibility in dairy camels are lacking. Sixty-five lactating camels in mid lactation, machine milked twice-daily and managed under intensive conditions were screened to evaluate the feasibility of utilising IRT compared with other routine indicators in detecting subclinical mastitis. Immediately before the morning milking, a portable infrared camera was used to obtain thermograms in duplicate for the front and rear left quarters to determine the udder surface temperature (UST). Thereafter, milk samples from quarters were collected, and processed for California mastitis test (CMT) score and somatic cell count (SCC). In the present study, CMT score was used to define subclinical mastitis and the feasibility of IRT to detect subclinical mastitis was compared with CMT and SCC. According to CMT score, subclinical mastitic udders had an average UST of 1·42 °C greater (P<0·0001) than healthy udders. The relationship between UST and CMT was found to be highly correlated (r=0·77; P<0·001), and UST was linearly increased as the CMT increased [UST (°C)=34·86+0·66×CMT score; R 2=0·65; P<0·001]. Additionally, high correlations were obtained between UST and SCC score (r=0·75; P<0·001) and the relationship between UST and SCC was fitted best to a logarithmic equation [UST, °C=33·39+0·88×Log (SCC, ×103 cells/ml), R 2=0·61, P<0·001]. The cut-off value, sensitivity, specificity and area under the receiver operating characteristics (ROC) curve for UST were 35·15 °C, 0·90, 0·98, and 0·95, respectively, when subclinical mastitis was defined according to CMT score, and were 35·70 °C, 0·89, 0·96 and 0·94, respectively, when categorised according to the obtained SCC threshold (SCC=432 000 cells/ml). In conclusion, IRT, as an indirect non-invasive screening method, was highly feasible for distinguishing subclinical mastitic udders in dairy camels, which is crucial to treat mastitis early and efficiently.