Bhaskaran Ravi Latha

Molecular prevalence of Cryptosporidium spp. in dairy calves in Southern states of India.

Dung samples were collected from dairy calves of south Indian states viz., Andhra Pradesh, Karnataka, Kerala, Tamil Nadu and union territory, Puducherry and are subjected to nested polymerase chain reaction (PCR) targeting 18S rRNA gene for detection of Cryptosporidium infection. Of the 459 dung samples screened 182 were found positive with a prevalence of 39.65%. Highest prevalence of Cryptosporidium was observed in Puducherry (86.67%) and lowest in Kerala (17.65%). Genotyping by PCR-restriction fragment length polymorphism (RFLP) and sequence analysis revealed the presence of all the four major Cryptosporidium species of cattle viz., Cryptosporidium andersoni, Cryptosporidium ryanae, Cryptosporidium parvum and Cryptosporidium bovis. C. andersoni was widely distributed in calves of Tamil Nadu, Karnataka and Puducherry whereas in Andhra Pradesh C. ryanae was the major species. Of the 64 samples subjected to PCR-RFLP, 39 (60.94%) could be classified as C. andersoni, 18 (28.13%) as C. ryanae, 4 (6.25%) as C. parvum and 3 (4.69%) were confirmed as C. bovis. The results were also confirmed by sequencing of 19 Cryptosporidium DNA samples.

In vivo immunomodulatory effects of ixodid ticks on ovine circulating T- and B-lymphocytes

Selected aspects of the ovine immune system were examined during the course of repeated infestations with the ixodid ticks, Haemaphysalis bispinosa and Hyalomma anatolicum anatolicum that naturally infest sheep, either individually or together. By the use of flow cytometry it was shown that total T‐lymphocyte numbers were significantly reduced from the sixth through the ninth days of all infestations. Gamma/delta (γδ+) and CD8+ T‐lymphocytes were significantly depleted during tick feeding in all infested groups. CD4+ T‐lymphocyte levels were significantly increased during secondary H. bispinosa and mixed species infestations. Hyalomma anatolicum anatolicum caused a significant increase in circulating B‐lymphocytes over several days in both initial and secondary infestations. All infested sheep had increased CD4/CD8 and decreased T/B lymphocyte ratios during exposure to both ticks. Bromodeoxyuridine (BrdU) ELISA was used to measure in vitro proliferation of peripheral blood mononuclear cells stimulated with the T‐lymphocyte mitogen Concanavalin A (Con A) after their collection from infested sheep. Significant suppression of in vitro proliferation occurred during first and secondary infestations with H. bispinosa, H. a. anatolicum and with both tick species together, beginning on the sixth day of infestation in all cases. These important tick species of sheep significantly modulate the numbers of immune effector cells and proliferation of T‐lymphocytes derived from infested animals.

Use of polymerase chain reaction: Restriction fragment length polymorphism to detect acaricidal resistance to synthetic pyrethroids in Boophilus microplus ticks of South India

Background: Boophilus microplus is an important ectoparasite of livestock. Apart from transmitting diseases, heavy tick burden can decrease production and damage hides. The synthetic pyrethroids which are advantageous over other acaricides for treatment of this infestation are now losing their efficacy due to development of resistant strains of ticks. Materials and Methods: Boophilus microplus ticks with a previous history of acaricidal treatment especially synthetic pyrethroids (SP) such as cypermethrin, deltamethrin and flumethrin were randomly collected from different pockets of four Southern States of India namely Tamil Nadu, Kerala, Karnataka, Andhra Pradesh, and Puducherry from cattle. Deoxyribonucleic acid extracted from pooled adult B. microplus tick from each State was subjected to polymerase chain reaction-restriction fragment length polymorphism to detect point mutation in carboxyl esterase gene. Results: A product size of 372 bp was obtained for cattle tick samples collected from all over Southern States of India. Conclusions: B. microplus ticks found in Southern part of India are not resistant to commonly used SP.

Kalicephalus sp. in a captive Russell's viper: a case report.

The occurrence of Kalicephalus sp. of hookworms in a Russell’s viper snake maintained in Chennai snake park trust, Chennai is reported. These worms were found in the stomach and intestine. They were cylindrical, thread like and had an elongate body. Anterior end was obliquely truncated with bivalvular buccal capsule. Short, thick and muscularised oesophagus ending in a rounded bulb was observed. In males, a well developed trilobed bursa was observed and the spicules were short and equal. Typical strongyle type eggs were found in the uterus of female worms as well as in the intestinal contents.

Occurrence of the pentastomid Porocephalus crotali (Humboldt, 1811) in an Indian rat snake (Ptyas mucosus): a case report

The occurrence of the pentastomid Porocephalus crotali in an Indian rat snake (Ptyas mucosus) at Chennai, India is reported. The worms were found in the lungs and they were identified as females. The worms were cylindrical and annulated with a centrally located mouth surrounded by four hooks. The worms were rounded in cross section with tapering ends. Eggs were composed of two shell membranes. This is one of the new reports from rat snakes in Southern India.

A six year (2006–2011) retrospective study of hemoprotozoan parasites affecting dogs in Chennai, Tamil Nadu, India

With the changing global scenario there is effect not only on the human survival but also on the prevalence of existing pathogens and appearance of new infectious agents among animal population. This paper emphasises the need for prevalence studies. A retrospective study for 6 years on prevalence of hemoprotozoans in dogs in Chennai showed Babesia gibsoni the predominant parasite of dogs. Details are discussed in this paper.

Sparganosis in Russell’s viper snake: a case report

The occurrence of the plerocercoid larva, Sparganum of Sparganum spp. in two Russell’s viper snakes maintained in Chennai snake park trust, Chennai is reported for the first time from Southern India. The cestode larvae were found in the sub cutis and were flat, solid, wrinkled, ribbon like creamy white in colour with peudosegmentation with anterior end possessing bothria. The cuticles, subcuticular cells and parenchymatous tissue stained by acetic alum carmine further confirmed the cestode larvae.

A novel approach to control brown dog tick, Rhipicephalus sanguineus using sustained release poly-ɛ-caprolactone-pheromone microspheres

Control of brown dog tick, Rhipicephalus sanguineus was attempted by utilizing sustained release preparations of synthetic analogues of assembly pheromones. The assembly pheromone, in defined ratio, was encapsulated using poly-ɛ-caprolactone by water-in-oil-in-water double emulsion solvent evaporation technique. In the in vitro bioassay, percent mortality with test microspheres was 95.6, 64 and 44 among the unfed larvae, unfed nymph and unfed adults respectively, 24 hours post-exposure. Field trials were carried out to evaluate the efficacy of microspheres in luring and killing environmental stages of R. sanguineus in dog houses/kennels. Engorged and unfed stages in the environment were found adhered and dead on the specially designed lure.

Response of unfed stages of Rhipicephalussanguineus to subtle variations in the composition of assembly pheromone

Two combinations of assembly pheromone (AP), with and without hematin were utilized as a lure for the unfed larvae, nymph and adults of Rhipicephalussanguineus ticks. In-vitro trials were carried out with the AP encapsulated in calcium alginate beads and the response of different stages of ticks were recorded. Analysis of results revealed that rapid attraction was evident in unfed larvae exposed to beads containing AP without hematin. In case of unfed nymphal and adult stages, the presence or absence of hematin did not have any impact on arrestment.

Occurrence of Laemobothrion maximum in Greater Coucal

External examination of free range abandoned dead Greater Coucal in a veterinary dispensary, Vellore, Tamil Nadu, India revealed presence of a large sized louse in the feathers and was identified as Laemobothrion maximum on the basis of morphology and size of the louse.