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.

The first molecular characterization of Sarcocystis cameli in the Indian dromedary camels (Camelus dromedarius)

In the present study, tissue samples (tongue, esophagus and heart) were investigated from dromedary camels of India for identification and characterization of Sarcocystis spp. using histopathology, PCR and gene sequencing. Genomic DNA extracted from these tissue samples was used for PCR amplification of the cytochrome c oxidase subunit I gene (cox1) of Sarcocystis spp. and the partial sequence of small subunit ribosomal RNA (18S rRNA) gene of the S. cameli. The PCR products were purified, sequenced and analyzed using bioinformatics tools. Based on phylogenetic analysis of the cox1 gene, the sequences of the present study clustered with those of S. cameli, hosted by dromedary camels of Iraq and a close association was observed with S. masoni hosted by dogs and alpacas of China. Until now, there are no 18S rRNA sequences of S. cameli available in GenBank and this is the first study recording 18S rRNA sequences of S. cameli which were grouped with S. masoni from alpaca of China and guanaco and llama of Argentina in phylogenetic analysis. These findings could be useful for further studies on the characterization through molecular epidemiology, genetic diversity and host specificity of S. cameli.

Case Report: Congenital tuberculosis in an aborted dromedary camel fetus

Tuberculosis (TB) is a serious public health problem worldwide, especially in tropical developing countries. Nevertheless, reports on congenital TB in humans and animals are extremely rare. In this study, abortion was reported in an 8-year-old she-camel at the 9th month of gestation. The she-camel appeared healthy in clinical examination, had a good body condition score, normal appetite, and had no signs of respiratory disease and fever. The expelled placenta was dark red-colored, thickened, and edematous with multifocal to coalescing ecchymotic hemorrhages on the allantoic surface. The striking finding was multiple, white-yellow, solid nodular lesions in the fetal lung, the pleura, and the liver. On histopathology, typical granulomatous lesions were detected in the lung and the liver characterized by caseous necrosis surrounded by lymphocyte and macrophage infiltration and concentric layers of fibrosis. The Ziehl-Neelsen staining detected scarce acid-fast bacilli in lung and liver tissues. The DNA extracted from tubercular lesions from the lung and liver showed amplification of the IS6110 region of the Mycobacterium tuberculosis complex by PCR. The sequencing and phylogenetic analysis revealed a close association of these sequences with Mycobacterium tuberculosis. The she-camel was detected positive for a single intradermal tuberculin test performed 24 h after abortion. This is the first report on congenital TB caused by M. tuberculosis in a dromedary camel fetus with a possible vertical transmission.

Pathological and molecular investigations of systemic form of camelpox in naturally infected adult male dromedary camels in India

Camelpox is a wide-spread infectious viral disease of camelids. An outbreak of camelpox was reported in 15 adult male dromedary camels aged between 10 to 16 years of an organized herd in winter season. The infected camels showed clinical signs of fever, anorexia, lachrymation, pendulous lips, excessive salivation and pock lesions on the skin of head, neck, mouth, lips, extremities, thigh, abdomen, scrotum and inguinal region. Mortalities were recorded in three infected camels after 10-12 days of infection and showed systemic pox lesions characterized by vesicles, papules, ulcerations and raised pock lesions in the mucous membranes of the mouth, tongue, tracheal mucosa, lung, abomasum and liver. Histopathology study revealed characteristic pox lesions with intracytoplasmic eosinophilic inclusion bodies in tongue. Lung showed lesion of interstitial pneumonia (n = 2) and bronchointerstitial pneumonia (n = 1). Liver showed infiltration of mononuclear cells around central veins and degenerative changes of hepatocytes. The abomasum and intestine showed ulcerations, marked capillary congestion and areas of lymphocyte infiltration in mucosa and submucosa. The presence of camelpox virus (CMLV) was confirmed in viral DNA isolated from formalin fixed paraffin embedded (FFPE) tissues of tongue, lung, abomasum, liver, heart and intestine of infected camels by C18L gene PCR. The sequencing of viral DNAs showed phylogenetic relatedness with other CMLV isolates from India and other countries. Thus, our study confirmed the rare severe form of systemic camelpox outbreak in adult male dromedary camels hence future attention should be given for studies on virulence, strain identification and molecular epidemiology of CMLV for planning of effective preventive and control strategies.

Fatal neonatal infection with Klebsiella pneumoniae in dromedary camels: pathology and molecular identification of isolates from four cases

In the present study, sudden mortalities were reported due to pneumonia in four neonatal camels (5 to 10 days old) of an organized dromedary camel farm. The clinical manifestations in affected camels were weakness, mild to high fever, not suckling, respiratory distress, and sudden death. On the basis of gross and histopathological lesions, the pneumonia was classified into bronchopneumonia (n = 2), bronchointerstitial pneumonia (n = 1), and interstitial pneumonia (n = 1). In bacterial culture, Klebsiella pneumoniae was isolated from lung of all the four cases. These bacteria were also confirmed by PCR from DNA isolated from culture as well as lung tissue. The sequencing of PCR products from four isolates of K. pneumoniae revealed homology with other pathogenic K. pneumoniae isolates from India and other countries. These findings confirmed the role of K. pneumoniae as an important etiological agent for causing pneumonia with sudden mortalities in suckling neonatal dromedary camels.

Characterization of GM-CSF-inhibitory factor and Uracil DNA glycosylase encoding genes from camel pseudocowpoxvirus

The present study describes the PCR amplification of GM-CSF-inhibitory factor (GIF) and Uracil DNA glycosylase (UDG) encoding genes of pseudocowpoxvirus (PCPV) from the Indian Dromedaries (Camelus dromedarius) infected with contagious ecthyma using the primers based on the corresponding gene sequences of human PCPV and reindeer PCPV, respectively. The length of GIF gene of PCPV obtained from camel is 795 bp and due to the addition of one cytosine residue at position 374 and one adenine residue at position 516, the open reading frame (ORF) got altered, resulting in the production of truncated polypeptide. The ORF of UDG encoding gene of camel PCPV is 696 bp encoding a polypeptide of 26.0 kDa. Comparison of amino acid sequence homologies of GIF and UDG of camel PCPV revealed that the camel PCPV is closer to ORFV and PCPV (reference stains of both human and reindeer), respectively.

Sequence analysis of topoisomerase gene of pseudocowpox virus isolates from camels (Camelus dromedarius)

Topoisomerase gene of pseudocowposvirus from Indian dromedarian camel was amplified by PCR using the primers of PCPV from Finnish reindeer and cloned into pGEM-T for sequence analysis. Analysis of amino acid identity revealed that Indian PCPV of camel shared 95.9-96.8 with PCPV of reindeer, 96.2-96.5 with ORFV and 87.5 with BPSV.