Efficacy of quantitative RT-PCR for detection of the nucleoprotein gene from different porcine rubulavirus strains.

Blue-eye disease is an emergent viral swine infection caused by porcine rubulavirus (PoRV). We have developed a qRT-PCR method to detect and quantify expression of the nucleoprotein gene for different PoRV strains. The limit of detection for this assay was 10(2) copies of synthetic RNA. Viral RNA from PoRV was detectable at a TCID50 of 0.01. Significant differences were observed between viral RNA quantification and virus titration results for nine PoRV strains. For nasal and oral swab samples that were collected from experimentally infected pigs, the qRT-PCR assay was more sensitive (87.1-83.9 %) for the detection of positive samples than methods involving isolation of virus. The implementation of highly sensitive assays that yield results quickly will be of great assistance in the eradication of PoRV from Mexico. We also believe that the newly developed qRT-PCR assay will help reduce the spread of this viral infection to other countries.

Persistence of porcine rubulavirus in experimentally infected boars.

Porcine rubulavirus is the etiological agent of blue eye disease in pigs. In boars, this virus causes orchitis and epididymitis and reduces seminal quality. The objective of this study was to determine the persistence of porcine rubulavirus in experimentally infected boars. Nine 12-month-old boars were infected with 5 ml of the PAC-3 strain of porcine rubulavirus at 1 × 10(5) TCID(50)/ml and held for 142 days post infection (DPI) to evaluate humoral immune response. The virus was isolated in cell cultures and detected by RT-PCR. Infection with porcine rubulavirus produced clinical signs beginning at 5 DPI. Necropsy results showed that 3 boars had lesions in the testicles and epididymes. Histological analysis showed the characteristic lesions in all infected boars. Porcine rubulavirus antibodies were detected in the second week post infection and increased significantly (P<0.05) over time. Isolation of the virus from semen was achieved between 5 DPI and 48 DPI and from the testicles and epididymes between 64 DPI and 142 DPI. Viral RNA was detected in the serum between 2 DPI and 64 DPI and in the semen until 142 DPI. These results confirm that the RNA of the porcine rubulavirus persists in the semen and that this virus remains in the reproductive tract for prolonged periods of infection. Semen of persistently infected boars, therefore, represents an important source of the virus and a risk factor for the spread of blue eye disease in swine populations.

Soil contamination by Toxocara spp. eggs in a university in Mexico City.

The contamination levels of Toxocara spp. eggs in soil samples from a university campus in Mexico City were evaluated and analysed according to garden size, and were related with the percentage of Toxocara spp. eggs and its viability according to the soil characteristics. A total of 1458 soil samples collected in 15 gardens (six large and nine small) were analysed by sedimentation-flotation with zinc sulphate solution on at 33%. Contamination was low (12.9%), and egg viability was high (65.5%). The size of the garden had no influence on the presence and viability of Toxocara spp. eggs. Contamination was negatively correlated with the percentage of vegetation (r = -0. 61, P < 0.01) and the viability was negatively associated with the percentage of clay in the soil samples (r = -0.51, P < 0.04). The size of the garden did not influence the presence and viability of Toxocara spp. eggs.

Contaminación por Toxocara spp. en parques de Tulyehualco México / Contamination for Toxocara spp. in Tulyehualco parks México

La toxocariasis es una parasitosis que afecta a los niños, en particular aquellos que juegan con tierra. Con el objetivo de identificar la presencia o incidencia de huevos de Toxocara spp., en parques de Tulyehualco, México, se realizó un análisis en muestras de suelos, heces depositadas en parques y muestras de heces de perros con propietario mediante un procedimiento de flotación-sedimentación. Los resultados mostraron una elevada contaminación por Toxocara, encontrando una contaminación de 60,0 por ciento en las muestras del suelo colectadas en los parques, 67,5 por ciento en heces colectadas en parques y 63,36 en heces de perros con propietarios. En los perros muestreados, no se encontraron diferencias por edad (P=0,27; menores de un año 65,47 por ciento; mayores de un año 55,55 por ciento), ni por sexo (¨P=0,5; hembras 55,55 por ciento; machos 63,45 por ciento). Se recomiendan algunas medidas para reducir la contaminación en suelos y disminuir la transmisión al hombre.

The toxocariasis is a parasitism that affects children, particularly those who play with soil. In order to identify the presence or egg incidence of Toxocara spp., in parks of Tulyehualco, Mexico; an analysis was conduced in samples of soils, feces deposited in parks and feces obtained from dogs with owners by a flotation-sedimentation procedure. The results demonstrated a high contamination by Toxocara, finding a contamination of in soil samples collected in the parks 60.0 percent, 67.5 percent in fecal samples collected in parks, and 63,36 in those obtained from dogs with owner, respectively. In sampled dogs, there were not differences by age (P=0.27; younger than 1 year 65.47 percent; older than one year 55.55 percent), neither by sex (¨P=0.5; female 55.55 percent; male 63.45 percent). Some measures are recommended to reduce the soil contamination and to diminish the transmission to the men.