Seroprevalence of bovine intestinal schistosomosis in different agro- ecological zones of south India using excretory-secretory antigen based ELISA.

Intestinal schistosmosis caused by Schistosoma spindale and S. indicum is an important snail borne trematode infection that adversely affects the production and productivity of bovines in India. The present communication reports the high seroprevalence of infection among dairy cattle and buffaloes, under field conditions, utilizing a sensitive and specific excretory-secretory antigen based ELISA. Comparison of ELISA with copro-PCR, microscopy and post-mortem mesentery examination revealed the diagnostic superiority of ELISA. Seroprevalence of infection was mapped for the first time in India with special emphasis to agro- ecological zones. Anti-schistosome antibodies were detected in 34.96% of dairy cattle and buffaloes in the state with the evidence of significant influence of topography on the prevalence of infection. The study also highlighted the need to trace endemic pockets of infection in the country through efficient ante-mortem surveillance and to initiate anti-schistosome therapy prior to animal transport.

Molecular detection of Hepatozoon canis in dogs from Kerala.

India has a wide range of agro-climatic zones which is highly conducive for a diverse range of vectors and canines are continuously exposed to the risk of spectrum of tick borne protozoan diseases. The brown dog tick, Rhipicephalus sanguineus is widely prevalent among dogs in Kerala and there is a high prevalence of this tick transmitted Babesia and Ehrlichia spp. infection. However, the incidence of Hepatozoon canis transmitted by the same tick species had not been reported in the state since 2004. Preliminary screening of client owned dogs revealed six dogs to be positive for typical gelatin capsule shaped gamonts of H. canis within neutrophils in blood smear by microscopic examination. A PCR assay was standardized to amplify a specific 737 bp fragment of 18S rRNA gene of H. canis. Phylogenetic analysis revealed closest relationship with West Indies isolate deposited at GenBank database. The present study records the molecular detection of this haemoparasite in the state, for the first time.

Efficacy of Dot-ELISA using different antigens in detecting anti-schistosome antibodies among bovines in field conditions.

Schistosomosis has been recognised as one of the major parasitic diseases of livestock and human beings. Schistosoma spindale is the major cause of visceral schistosomosis among bovines of Kerala State. Besides pathology in animals, it has been long known that cercariae of S. spindale are a common cause of dermatitis in human beings in Asia. However, detection of this disease based on coprology has underestimated the prevalence of this economically important disease among cattle of the State. An efficient diagnostic tool providing unequivocal evidence of infection in living animals is perhaps, the key to formulate and deliver control measures to the target population. It is also crucial for an enhanced understanding of parasite epidemiology. The utility of excretory-secretory proteins as diagnostic and vaccine candidates for schistosomosis has been a focus of medical research since long. There exists a paucity of information with regard to analysis of ES proteins of S. spindale and their incorporation to develop sensitive and specific serodiagnostic tool. Hence a study was designed to evaluate the efficacy of Dot-ELISA incorporating different antigens of S. spindale and to validate the test under field conditions.

Copro-PCR based detection of bovine schistosome infection in India.

Schistosomosis and amphistomosis are the two economically important and widely prevalent snail-borne trematode infections in grazing cattle of southern India. Acute infections are symptomatically similar and difficult to detect by routine microscopy for eggs. The present study was directed towards the development of a copro-polymerase chain reaction (copro-PCR) for detection of bovine schistosome species, using custom-designed primers targeting 18S and 28S ribosomal RNA as well as mitochondrial DNA. The study demonstrated the enhanced diagnostic specificity of mitochondrial DNA markers over ribosomal RNA genes as genus-specific probes to detect schistosomes. We developed a sensitive PCR assay using primers designed from mitochondrial DNA sequences targeting the partial rrnl (16S rRNA), tCys (transfer RNA for cysteine) and partial rrnS (12S rRNA) genes of Schistosoma spindale to specifically detect schistosome infection from faecal samples of naturally infected bovines. The salient findings of the work also throw light on to the high similarity of the ribosomal RNA gene sequences of schistosomes with those of Gastrothylax crumenifer and Fischoederius elongatus, the most prevalent pouched amphistomes of the region. Further investigation has to be directed towards unravelling the complete gene sequences of 18S and 28S ribosomal RNA as well as mitochondrial DNA sequences of amphistome isolates from India.

Occurrence of human sparganosis in Kerala.

Human sparganosis is a rare zoonotic disease caused by the larval stages of Spirometra sp. A seven cm worm recovered from a painful swelling in the right inguinal region of a 9 year old boy from Kunnamkulam in Thrissur District, Kerala was identified as sparganum based on morphology. This is the first case report of the disease from Kerala state. Possible mode of infection and control measures are suggested. Increased public awareness about risks associated with drinking contaminated water is important to prevent further incidence in the locality.

Molecular characterization of Theileria orientalis causing fatal infection in crossbred adult bovines of South India.

The disease condition attributed to have been caused by Theileria orientalis is generally benign. However, it is also thought that the parasite, at least some strains of it, can cause fatal disease. The present communication deals with the clinical signs, postmortem lesions and diagnosis of a fatal disease due to T. orientalis which caused mortality in crossbred adult bovines of South India. High body temperature, lacrimation, nasal discharge, swollen lymph nodes and haemoglobinuria were the symptoms observed. The postmortem lesions observed were punched out ulcers in abomasum, enlargement of spleen, massive pulmonary oedema, frothy exudates in trachea, epicardial and endocardial haemorrhage and haemorrhagic duodenitis. Peripheral blood smear examination revealed rod shaped Theileria sp. organisms. Polymerase chain reaction that amplify the T. orientalis specific P(32/33) gene, followed by cloning and sequencing, revealed maximum homology with Narathiwat (Thailand) and Jingole -1 (Indonesia) isolates which were positioned as isolate type 7 of T. orientalis.

Dirofilariosis in dogs and humans in Kerala.

There has been an increased occurrence of filarial worms in the subcutaneous tissues and subconjunctival space of human beings belonging to different areas of the state of Kerala. The present work was carried out to identify the worms recovered from human cases, to study the presence of microfilariae in dogs and to discuss the possible mode of infection in human beings. Twelve worm specimens from human patients received in the Department of Veterinary Parasitology, College of Veterinary and Animal Sciences, Mannuthy from 2002 to 2004 were identified as Dirofilaria repens based on morphology. Out of the 160 blood smears of dogs examined during the same period, microfilariae were detected in 11 samples (7%). With 7 per cent dogs positive for microfilariae of D. repens in Kerala, it is suggested that human beings are at an enhanced risk of acquiring dirofilaria infection.

Serologic prevalence of Toxoplasma gondii in chickens in Madras, India.

Serum samples from 185 chickens (Gallus gallus) collected from the various slaughter markets in and around Madras City, India were examined for antibodies to Toxoplasma gondii using the modified agglutination test incorporating mercaptoethanol. Antibodies (> or = 1:25) to T. gondii were found in 39.5% of sera. Antibody titers of individual sera (% in parentheses) were 1:25 (8.1%), 1:50 (10.8%), 1:100 (6.5%), 1:200(2.7%), 1:400 (4.3%), 1:800 (5.9%) 1:1,600 (0.5%), and 1:3,200 (0.5%).