Gerardo Enrique Medina-Basulto

Field evaluation of the protective efficacy of Mycobacterium bovis BCG vaccine against bovine tuberculosis

The protective efficacy of Mycobacterium bovis BCG (1 x 10(6) single dose) was evaluated under field conditions. A total of 140 male Holstein Friesian calves, one to two week-old were selected. Two groups of 70 each were formed, one group was vaccinated and the other was injected with a placebo during their second week of age and followed until 12 months of age. The study considered a positive case of tuberculosis to be an animal that had a positive reaction to the three following tests in a row: tuberculin, IFNgamma PPD-B and IFNgamma ESAT6-CFP10 during the 12 months of exposure. The results showed a 59.4% efficacy (IC95%: 47.64-71.16). The non-vaccinated calves were 2.4 times more at risk of becoming infected (IC95%: 1.07-5.68) compared to vaccinated animals. As a complementary test a PCR test was performed using nasal exudates in some animals from both groups using a Mycobacterium complex detection kit. All the positive PCR reactions (5/44) were found in the non-vaccinated animals. These findings suggest that the use of the BCG vaccine, even though it is not capable of protecting 100%, does prevent TB vaccinated animals from excreting bacilli in their nasal secretions at their first year of age.

Prevalence and distribution of intestinal parasites in stray dogs in the northwest area of Mexico

espanolRESUMEN: Las infecciones zoonoticas parasitarias son un problema global publico y para la medicina veterinaria, siendo diseminadas por perros callejeros. El objetivo del estudio fue determinar la prevalencia de parasitosis intestinales en perros callejeros de la zona urbana, rural y costera del municipio de Mexicali, noroeste de Mexico. En 2014, entre enero y diciembre, se capturaron 380 perros. Se colecto el intestino, ciego y heces y se examinaron utilizando flotacion con sulfato de zinc y tincion con la solucion de Lugol. Los datos fueron analizados estadisticamente. En general, alrededor del 21,5% de los perros examinados fueron positivos a parasitos intestinales. Toxocara canis fue el parasito mas frecuentemente, con una prevalencia del 7,1%, seguido por Toxascaris leonina (5,5%), Cystoisospora spp. (5,0%), Taenia spp. (3,9%) y Dipylidium caninum (2,8%). Los perros fueron mas frecuentemente encontrados infectados con un solo genero de parasito intestinal (18,7%) que coinfectados (2,8%). Las parasitosis intestinales fueron mas prevalentes en muestras de la costa (25%) que del area rural (24,4%) y urbana (20,6%), sin embargo solo se encontro asociacion estadistica entre el area de captura y las parasitosis intestinales especificas. Hubo diferencias significativas en la prevalencia de taeniasis entre los dos grupos de edad (P EnglishABSTRACT: Zoonotic parasitic infections are a major global public and veterinary health problem and widespread among stray dogs. The objective of this study was to establish the prevalence of intestinal parasites in stray dogs in the urban, rural and coastal areas of Mexicali County in northwest Mexico. In 2014, from January to December, 380 stray dogs were captured. The entire small intestine, cecum and faeces samples were collected and examined by using simple zinc sulfate flotation and Lugol’s solution staining. Data were statistically analysed. Overall, about 21.5% of examined dogs were found positive for intestinal parasites. Toxocara canis was the most frequent detected parasite, with a prevalence of 7.1%, followed by Toxascaris leonina (5.5%), Cystoisospora spp. (5.0%), Taenia spp. (3.9%) and Dipylidium caninum (2.8%). Dogs were more frequently found to be infected with a single genus of intestinal parasite (18.7%) than co-infected (2.8%). Intestinal parasites were more prevalent in samples from the coastal area (25%) than in those from the rural (24.4%) and urban (20.6%) areas, however, only statistical association was found between capture area and specific intestinal parasitic infection. There were significant differences in the prevalence of taeniasis among two age groups (P

Evaluation of two in-house immunoenzymatic tests to serodiagnose subclinical paratuberculisis in a sheep flock in Mexicali valley, Mexico

ABSTRACT Paratuberculosis (PTB) or Johne’s disease is a common ruminant infectious disease caused by Mycobacterium avium subsp. paratuberculosis (MAP). In this study, two MAP antigens were compared for their diagnostic utility to detect subclinical PTB in a sheep flock in Mexicali, Mexico. Sheep (n = 31) without clinical signs but positive on a direct fecal-polymerase chain reaction were tested with two preabsorbed in-house enzyme linked immunosorbent assays (ELISAs) using: (1) an ethanol-extracted surface lipid antigen (EVELISA) and (2) a protoplasmic antigen (ELISA-PPA). Sensitivities of the EVELISA and ELISA-PPA were 84% (95% CI; 66–95%) and 29% (95% CI; 14–48%), respectively. The EVELISA test could be a fast and effective way to identify subclinical ovine PTB for severely affected flocks.

Mycobacterium avium subsp. paratuberculosis down-regulates mRNA expression of iron-induced macrophage Ferroportin 1

Distributed under Creative Commons CC-BY 4.0 Abstract Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of Johne’s disease. The mechanisms by which MAP is able to adapt to the innate host response are still unclear. We examined Ferroportin 1 (FPN1) mRNA expression levels via real-time PCR of the mouse macrophage cell line J774 that was incubated in the presence of Mycobacterium avium subsp. paratuberculosis (MAP) or MAP crude protein extract. Infection with live MAP decreased FPN1 mRNA levels in a multiplicity of infection (MOI)-dependent fashion. Macrophages infected with MOIs of 20:1 and 15:1 did not show any change in FPN1 gene expression, whereas MOIs of 10:1 and 5:1 induced a decrease of 50 and 80%, respectively. Macrophages treated with 50, 100, 150 and 200 μg/mL of MAP crude extract (ATCC19698) decreased FPN1 mRNA expression by 25%. Additionally, up-regulation of FPN1 mRNA by an iron overload treatment of 400 μM of ferric nitrilotriacetate (FeNTA) was abrogated by live MAP (MOI 20:1) by approximately 70%. Our data revealed an inhibitory effect of MAP on FPN1 mRNA and suggested a bacterial mechanism that may play a role in host iron regulation.

Evaluating protective efficacy of a BCG vaccine against TB in a field trial in cattle

VACCINATION of cattle against Mycobacterium bovis is being considered as one possible tool in the control of bovine tuberculosis (TB). The BCG vaccine has been shown to provide some protection against M bovis infection, but further research is needed on its efficacy under natural conditions. This