Publication Date: 1999.
Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). In Argentina, where a program to eradicate EBL has been introduced, sensitive and reliable diagnosis has attained high priority. Although the importance of the agar gel immunodiffusion test remains unchanged for routine work, an additional diagnostic technique is necessary to confirm cases of sera with equivocal results or of calves carrying maternal antibodies. Utilizing a nested shuttle polymerase chain reaction, the proviral DNA was detected from cows experimentally infected with as little as 5 ml of whole blood from BLV seropositive cows that were nonetheless normal in haematological terms. It proved to be a very sensitive technique, since it rapidly revealed the presence of the provirus, frequently at 2 weeks postinoculation and using a two-round procedure of nested PCR taking only 3 hours. Additionally, the primers used flanked a portion of the viral genome often employed to differentiate BLV type applying BamHI digestion. It is concluded that this method might offer a highly promising diagnostic tool for BLV infection.
Facultad de Ciencias Veterinarias
Repository: SEDICI (UNLP). Universidad Nacional de La Plata
Authors: Romero-Salas, Dora; Mira, Anabela; Mosqueda, Juan; García Vázquez, Zeferino; Hidalgo Ruiz, Mario; Vela, Noot Aditya Ortiz; de León, Adalberto Ángel Pérez; Florín Christensen, Monica; Schnittger, Leonhard
Publication Date: 2016.
Babesia bovis and Babesia bigemina are causative agents of bovine babesiosis, a tick-borne disease of cattle in tropical and subtropical regions. Babesia spp. infection adversely affects cattle health and can be fatal resulting in considerable economic loss worldwide. Under endemic stability conditions, herds contain high numbers of chronically infected, asymptomatic carrier animals, in which no parasitemia is detected by microscopic blood smear examination. In addition to bovines, also water buffaloes are infected by both Babesia spp. commonly leading to a subclinical infection. The infection rate (by nPCR) and herd exposure (by IFAT) of bovines and water buffaloes reared under similar field conditions in an area of endemic stability were determined and compared. In order to optimize direct parasite detection, highly sensitive nPCR assays were developed and applied, allowing the detection of as little as 0.1 fg DNA of each Babesia pathogen. Significantly lower percentages (p < 0.001) of seropositive water buffaloes compared to bovines were observed for B. bovis (71.4% vs. 98%) and B. bigemina (85% vs. 100%). Interestingly, in comparison, differences noticed between water buffaloes and bovines were considerably larger with direct parasite detection by nPCR (16.2% vs. 82.3% and 24% vs. 94.1% for B. bovis and B. bigemina, respectively).As expected, bovines subjected to monthly acaricide applications exhibited a significant lower infection rate as determined by nPCR than bovines not subjected to these measures (B. bovis 33.3% vs. 90.7%, p < 0.001; B. bigemina 80% vs. 96.5%, p < 0.001, for treated vs. untreated animals). Interestingly no differences between these groups were observed with respect to seropositivity, suggesting similar rates of parasite exposure (B. bovis 100% vs. 97.7%, p < 0.001; B. bigemina 100% vs. 100%, p < 0.001). Importantly, a significantly higher number of water buffaloes as determined by nPCR were infected when reared jointly with bovines not subjected to tick control than when reared jointly with bovines subjected to tick control (B. bovis 31.6% vs. 9.5%, p < 0.01; B. bigemina 42.1% vs. 9.5%, p < 0.01, for water buffaloes reared with untreated vs. treated bovines) and/or when reared without bovines (B. bovis 31.6% vs. 11.6%, p < 0.01; B. bigemina 42.1% vs. 20%, p < 0.01). An accumulation of seropositivity and a decline of infection rates were observed in older animals, while differences observed with regard to gender may warrant further investigation. In summary, our findings suggest that water buffaloes are much more capable to limit or eliminate Babesia infection, possibly due to a more capable immune defense. Furthermore, an increased Babesia spp. parasite reservoir of bovines seems to increase the infection rate of water buffaloes when both are reared on the same pasture.
Author affiliation: Romero-Salas, Dora. Universidad Veracruzana; México
Author affiliation: Mira, Anabela. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina
Author affiliation: Mosqueda, Juan. Universidad Autónoma de Querétaro; México
Author affiliation: García Vázquez, Zeferino. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias. Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria; México
Author affiliation: Hidalgo Ruiz, Mario. Universidad Autónoma de Querétaro; México
Author affiliation: Vela, Noot Aditya Ortiz. Universidad Veracruzana; México
Author affiliation: de León, Adalberto Ángel Pérez. United States Department of Agriculture. Agricultural Research Service; Argentina
Author affiliation: Florín Christensen, Monica. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias. Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria; México
Author affiliation: Schnittger, Leonhard. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias. Centro Nacional de Investigación Disciplinaria en Parasitología Veterinaria; México
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas