Prabhat Chandra Sarmah

Prevalence and molecular epidemiological data on Dirofilaria immitis in dogs from Northeastern States of India.

The aim of the present study was to determine the prevalence of Dirofilaria immitis in stray, pet, and working dogs (n = 413, 266, and 103, resp.) from Guwahati (Assam) and Aizawl (Mizoram), areas located in two Northeastern States of India. Diagnostic methods applied were microscopy (wet film and Knotts concentration technique), immunological test (Ag ELISA by SNAP 4Dx ELISA kit), and molecular tools (polymerase chain reaction and sequencing), which evidenced 11.38, 18.03, and 13.93% of positive animals, respectively. No significant differences were observed by area (18.23% versus 17.68%) nor by sex (18.1% versus 17.9%), whereas stray dogs proved more infected than other groups (P < 0.05). ELISA test evidenced an overall 22.69% of occult infections, mainly in working dogs (60%), and molecular techniques detected Dirofilaria (Nochtiella) repens in 4 stray dogs from Guwahati. Characterization of D. immitis isolates for ITS-2 region showed close identity with South Asian isolates.

Emergence of oriental theileriosis in cattle and its transmission through Rhipicephalus (Boophilus) microplus in Assam, India

Aim: The aim of the present study was to investigate the presence of Theileria in blood samples of crossbred and indigenous adult cows raised under unorganized small scale farming system in a Babesia and Anaplasma endemic geographical area from Assam, India and to see its transmission through Rhipicephalus (Boophilus) microplus ticks. Materials and Methods: For the present study, 57 clinical cases of cattle suspected to be of hemoparasitic infections were taken into consideration. The parasites were identified based on morphology in giemsa stained blood smear followed by polymerase chain reaction (PCR). Sera samples were tested for T. annulata antibodies in plate and Dot-ELISA. PCR was also conducted in eggs of Rhipicephalus (Boophilus) microplus tick collected from a Theileria orientalis positive animal. Results: PCR amplified 1124, 776, and 160 bp DNA fragments of B. bigemina (64.91%), T. orientalis (21.05%) and A. marginale (14.03%), respectively. This assay further conducted in 12 T. orientalis positive blood samples with primers of Buffeli, Chitose, and Ikeda variants of T. orientalis showed 3 samples positive to Ikeda type and none for Buffeli and Chitose. Babesia bovis and Theileria annulata specific primers also did not amplify any fragment during the PCR assay of the blood samples. Further, all sera samples tested negative to T. annulata antibodies in Plate and Dot-ELISA. PCR conducted in eggs of R (B).microplus tick collected from a T. orientalis positive animal revealed presence of the parasite DNA. Gradual improvement in physical condition leading to complete recovery in 10 out of 12 T. orientalis infected clinical cases treated with buparvaquone(at 2.5mg/kg.b.wt I/M) was the feedback obtained from field veterinarians and the cattle owners. Conclusion: The present investigation represents the first report of occurrence of T. orientalis in cattle of Assam with involvement of pathogenic Ikeda strain in clinical outbreaks and its possible natural transmission by R (B). microplus through the transovarian mode.

Epidemiological aspects of Dirofilaria immitis infection in dogs from Assam of Northeast India

Abstract Objective To analyze the epidemiology of Dirofilaria immitis ( D. immitis ) infection in different categories of dogs in Assam. Methods Microscopy of blood in wet film preparation was conducted in two dog populations during 2009 and 2010, and data obtained were analyzed to investigate the infection pattern according to season, living condition, breed, sex and age of dogs. Results Examination of 424 clinically ill dogs (hospital population) presented at the referral Teaching Veterinary Clinical Complex, Guwahati, Assam revealed 5.42% cases microfilaraemic. Clinical cases of D. immitis infection were recorded throughout the year with 9.10% as the highest record during pre-monsoon and 1.12% as the lowest in the winter. Pet dogs staying indoor showed 4.76% microfilaria positive compared to 7.95% record among working dogs with restricted outdoor activity. Breed wise, Dalmatian dogs representing 3.53% of the study population were negative to microfilaria while among the positives, Doberman showed 30.76% infection rate as the highest and 2.94% lowest record in the Labrador. Rate of infection was slightly higher in the males (5.81%) than the females (4.81%). Dogs below 2 years of age were negative to microfilaria while it was 3.70% in 2–4 years age group with a rising trend reaching 28.00% as the highest in 6–8 years age group. Examination of non-descript (street dog population) adult dogs living outdoor showed 29.54% microfilaraemic, the rate of infection being higher in males (37.50%) than the females (25.00%). Similar non-descript dogs living indoor as pets however showed only 11.11% microfilaria positive. Conclusions The study shows endemicity of D. immitis in dogs of Assam with living condition and age as the host related important risk factors, which have significant role in its epidemiology.

Gastrointestinal nematode larvae in the grazing land of cattle in Guwahati, Assam

Aim: To know the prevalence of gastrointestinal nematode larvae (L3) in the grazing land of cattle in Guwahati, Kamrup district, Assam. Materials and Methods: Pastures were collected and examined for the presence of nematode larvae (L3) from six localities of Guwahati at monthly interval from August 2012 to July 2013. The counted larvae were then expressed as per kg dry matter of herbage (L3/kg DM). Results: Examination of pastures revealed presence of nematode larvae (L3) in pastures throughout the year which varied from 4.5 L3/kg DM in January to a maximum of 106.33 L3/kg DM in August. The L3 of Haemonchus contortus, Trichostrongylus spp., Oesophagostomum spp., Cooperia spp., and Mecistocirrus spp. were recovered from pastures. The average pasture larval burden (PLB) was 34.75±3.48 L3/kg DM. Season-wise PLB revealed the presence of 23.89±3.01, 67.54±5.41, 26.67±1.92, and 7.28±0.89 L3/kg DM during pre-monsoon, monsoon, post-monsoon, and winter seasons, respectively. Monsoon season has significant (p<0.05) effect on PLB. However, analysis of variance of different locations with respect to season revealed that there was no significant difference but season-wise it was highly significant (p<0.01). Pearson correlation of environmental variables (temperature, relative humidity, and rainfall) with PLB revealed correlation was statistically significant with rainfall (p<0.05). Conclusion: This study reveals the presence of five nematode larvae (L3) in the pastures of Guwahati, Assam throughout the year, statistically significant during monsoon season.

Diversity of Eimeria spp. in dairy cattle of Guwahati, Assam, India

Aim: To determine the prevalence and diversity of Eimeria spp. in dairy cattle present in and around Guwahati, Kamrup district, Assam, India. Materials and Methods: A total of 2339 fecal samples of calves (535), heifer (641) and adult (1163) cattle were screened for 1 year present in and around Guwahati, Assam for detection of Eimeria oocysts by flotation techniques. Sporulation of the oocyst was done in 2.5% potassium dichromate solution for identification of the Eimeria species. Results: Examination of fecal samples revealed an overall prevalence of 11.97% Eimeria infection in dairy cattle of Guwahati, Assam. Age-wise, 33.2%, 45.4%, and 21.4% infections were recorded in calves (<1 year), heifer (1-3 years) and adult (>3 years) cattle, respectively. Season-wise, infection was recorded highest during post-monsoon (16.29%), followed by monsoon (15%), winter (9.44%), and pre-monsoon (7.49%) season. Seven species of Eimeria were recorded viz. Eimeria bovis, Eimeria zuernii, Eimeria subspherica, Eimeria bukidnonensis, Eimeria auburnensis, Eimeria ellipsoidalis and Eimeria alabamensis. The oocyst count per gram of feces ranged from 50 to 1500 in infected cattle. Conclusion: This study indicates that there is the prevalence of seven species of Eimeria in dairy cattle of Guwahati, Assam and mostly prevalent during the post-monsoon season.

Dirofilaria repens in dogs from Assam, India

Abstract Objective To access the prevalence of Dirofilaria repens (D. repens) in dogs from Assam, India. Methods A total of 223 blood samples from local dogs were examined with conventional (wet film and Knotts concentration technique), serological (ELISA test using Snap4Dx kits) and molecular techniques (targeting internal transcribed spacer-2 region using panfilarial primers) in Guwahati, Assam, India. Results The study revealed 4 (1.79%) cases of asymptomatic canine dirofilariasis caused by D. repens. The blood samples were positive for D. repens with microfilaremia on wet blood film, at Giemsa stained smear and under Knotts concentration technique, but were negative at Snap®4Dx test (IDEXX Laboratory, Westbrook, USA) which is specific for Dirofilaria immitis. D. repens could be detected by molecular test. Further confirmation was obtained on the basis of DNA sequencing and homology searching by basic local alignment search tool. Sequence analysis revealed that the species prevalent in Guwahati was genetically distinct from the other D. repens reported from elsewhere. Conclusions Occurrence of D. repens in dogs from this part of India was recorded for the first time, confirming the presence of a autochthonous canine reservoir for the zoonotic filarial nematode in Assam, India, where three cases of human subcutaneous and ocular infection with D. repens (dirofilariasis) have been reported.