RESUMEN

Bovine alphaherpesvirus-1 (BoAHV-1) is an important viral pathogen that causes significant economic losses to the dairy industry. The present study aimed to determine the prevalence of BoAHV-1 in cases of bovine reproductive disorder. Clinical samples were collected from various villages in Gujarat using specialized FTA® cards and were tested using real-time PCR assay targeting the gB gene of BoAHV-1. Out of 401 animals, 18.20% (95% CI: 14.74-22.28%) tested positive for BoAHV-1 DNA. The percentage positivity of BoAHV-1 was 20.37% in abortion cases and 19.55% in retention of fetal membrane cases, while only one out of nine metritis cases screened in the study was positive for BoAHV-1 DNA. A higher percentage positivity in buffaloes (22.14%) compared to cattle (16.30%) was recorded, but this difference was not statistically significant (p = 0.169). The frequency of BoAHV-1 detection was higher among crossbreeds (16.76%) and exotics (19.61%) than among indigenous cattle (8.82%), although this difference was not statistically significant (p = 0.400). There was also no significant difference in frequency distribution among animals of varying parity, ranging from 15.20 to 33.33% (p = 0.540). This study confirms the widespread circulation of BoAHV-1 and highlights the need for its control and prevention.

RESUMEN

Background: Information on the prevalence of infectious agents in dairy farms forms the basis for formulating a suitable control strategy; especially in endemic situations. Aims: A cross-sectional study was undertaken to determine the prevalence of six economically important bovine diseases, causing reproductive disorders including bovine abortion in organized dairy herds in India. Methods: A total of 1,075 animals (cattle and buffaloes) from 09 dairy farms were screened by ELISA tests. Results: Bovine viral diarrhoea (BVD) was the most prevalent (56.5%) disease followed by infectious bovine rhinotracheitis (IBR) (45.4%). Prevalence of Q-fever (5.4%) and neosporosis (6.1%) were less on the farms. Although 16.3% of the samples turned positive for brucellosis, the contribution of calf-hood vaccination (B. abortus S19 vaccine) to the prevalence of antibodies cannot be ruled out. The overall prevalence of bovine anaplasmosis, known to cause sporadic abortions in dairy herds, was 34.1% in the 9 farms with a prevalence of less than 20% in 5 farms. Infection of multiple abortifacient (seroprevalence to more than two pathogens) was recorded in 56.8% of animals. A very strong association was observed between BVD and brucellosis (Odds ratio 14.2; P<0.001). Further, a positive association was also seen between seroprevalence of IBR and anaplasmosis, and neosporosis and Q fever (P<0.05). Conclusion: Viral diseases were found to be more common in the dairy herds than bacterial and protozoan diseases. Increased susceptibility of IBR seropositive cows to other bacterial and viral infections was observed.

RESUMEN

Foot-and-mouth disease (FMD) is a highly contagious and rapidly transmissible disease of cloven footed animals. Emergence of genetically divergent strains of FMD virus (FMDV) is a major concern globally. FMD is endemic in India and three serotypes (O, A and Asia 1) prevail. The study was undertaken to characterize the isolates from the state of Odisha, India both genetically and antigenically. FMDV was detected in 7 of the 17 clinical samples collected from FMD affected/suspected animals, in which serotype O and A were found in three and four samples, respectively. Serotype O field isolates clustered in an unnamed group (designated here as Eastern cluster) circulating mostly in the Eastern region of the country and had 10-12.7% divergence from the Ind2001 lineage circulating predominantly throughout the country. The serotype A isolates sequenced in this study was grouped within VP359-deletion group of genotype 18, precisely in clade 18c, having high genetic homology to the virus circulating in the neighboring states, suggesting interstate movement. Both the serotype O and A isolates showed good antigenic relationship value with the respective vaccine strains currently used in the country.

RESUMEN

Multilocus sequence typing (MLST), a sequence-based typing method for bacterial pathogens, is currently the best method for long-term epidemiological study and to understand the population structure of the bacteria. This investigation was carried out to study the diversity of Pasteurella multocida isolates circulating in India. Ten different sequence types (ST) identified in this study are ST 122 from cattle, goat, mithun and pig; ST 50 from pig; ST 9 from cattle and sheep; ST 229 from cattle and goat; ST 71 and ST 277 from cattle; and ST 129, ST 280, ST 281 and ST 282 from avian species. Of these, ST 277, ST 280, ST 281 and ST 282 were identified for the first time. The analysis of results provides novel epidemiological information on the circulation of multiple STs across India. The majority of STs or their variants identified in this study have already been reported from different parts of the globe. This suggests that probably transboundary spread of strains across countries and continents has occurred across evolutionary time and is still happening. The isolation of ST 122 from small ruminants and pigs suggests that these species may be included in the preventive vaccination policy for effective control of haemorrhagic septicaemia in India.

Asunto(s)

RESUMEN

RNA virus population exists as a complex distribution of non-identical but closely related sequences known as viral quasispecies. Variant strains are selected from this quasispecies population in response to changing environment. The quasispecies dynamics of a virus existing within an infected host differs from that in a cell culture-adapted population. This study was carried out to explore the genetic variations present in the VP1 coding region of the foot-and-mouth disease (FMD) virus serotype O derived directly from infected cattle tongue epithelium. Molecular clonal populations of two serotype O strains belonging to lineages Ind2001 (IND 30/2011) and PanAsia2 (IND 5/2011) were sequenced at VP1 coding region. For IND 30/2011, 19 clones were sequenced and analysis showed variations at 12 nucleotide positions (nt) resulting in 8 amino acid (aa) replacements. Similarly, for IND 5/2011 virus, 18 clones were sequenced, of which six showed nt variations leading to 3 aa replacements. Most of the variable positions mapped to the surface-exposed loops and some of them were found in the neutralizing antigenic sites (position 81, 149, 169, 186 and 202 of IND 30/2011 and 141 of IND 5/2011), which potentially could be beneficial in rapid adaptive evolution of the virus by giving rise to antigenic variants to overcome neutralizing antibodies. These findings encourage further research into the landscape of the viral quasispecies population in vivo and its implication for viral ecology.

Asunto(s)

RESUMEN

India is endemic for foot-and-mouth disease (FMD), and goats constitute the second largest susceptible population of domestic livestock. FMD surveillance and control strategies in the country largely ignore small ruminants, known to be critical in the epidemiology of the disease. Here, serological investigations were carried out to generate estimates of antibody prevalence in goats of Orissa state to both non-structural (NSP-Ab) and structural proteins (SP-Ab) of FMD. The apparent overall NSP-Ab and SP-Ab seroprevalences were 38% and 20.7%, respectively, which signifies a very high level of FMD virus circulation in the goat population despite the lack of clinical signs in this species. The apparent prevalence of NSP-Ab and SP-Ab was positively correlated in the sampling areas. Interestingly, the values found for NSP-Ab prevalence were almost consistently higher than those found for SP-Ab prevalence. This could have been attributable to either issues related to sensitivity and specificity of the test systems employed or differences in the post-infection kinetics of NSP- and SP-Ab. The pattern that emerged from SP-Ab analysis indicated goats being infected with all three prevalent serotypes (O, A and Asia 1) and reinforces the concept that non-vaccinated goats can be exploited as tracer animals for detecting serotypes involved in outbreaks. The results underscore the requirement to bring caprine species under comprehensive surveillance and vaccination campaigns to check silent amplification, excretion and transmission of the virus.

Asunto(s)