Vector control efficacy of fly nets on preventing bovine leukemia virus transmission

Kohara, Junko; Miki, Tsuneharu; Hirano, Yuki; Sakurai, Yoshie; Takahashi, Toshihiko

doi:10.1292/jvms.18-0199

Cited by 26 publications

(17 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The vector infestation (OR = 2.07, P < 0.01), favored by the inadequate management of manure, lack of parasitic control, and the Amazonian climate, allows the inoculation of infectious agents, such as BLV, during blood repast [16,30,35]. Rectal palpation for the diagnosis of gestation without changing gloves (OR = 1.90; P < 0.01) is, in turn, a very common procedure in the farms, and allows the iatrogenic transmission of the virus through small excoriations in the rectum wall [24].…”

Section: Discussionmentioning

confidence: 99%

“…Enzootic bovine leukosis (EBL) is an infectious and chronic disease of great relevance to livestock production [18], caused by an oncogenic retrovirus denominated bovine leukosis virus (BLV) [10,32]. The transmission occurs through the hematogenous pathway and is associated to flaws in hygienicsanitary management of livestock, especially in an iatrogenic form, through the bite of hematophagous insect, or still by ingestion of fresh milk by neonates [16,17,24,27,30,34]. The World Organization for Animal Health recommends the mandatory notification of this disease and the slaughter of all infected animals [28].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Risk Factors for Enzootic Leukosis in Dairy Cattle from the Brazilian Amazon

Silva

Melchior

Reckziegel

et al. 2019

Acta Scientiae. Vet.

View full text Add to dashboard Cite

Background: Enzootic bovine leukosis (EBL) is a viral and lymphoproliferative disease that attributes negative economic impacts to dairy farming. The immunosuppressive condition of these bovines favors the development of bacterial diseases such as tuberculosis, brucellosis, and bovine leptospirosis, which implications to the public health given that they are zoonosis. Diagnosis and control of EBL are neglected in cattle rearing, allowing their dissemination, especially in developing countries. In this sense, the objective of this study was to analyze the risk factors of EBL in dairy cattle from the Brazilian Amazon. Materials, Methods & Results:In order to identify the BLV-infected animals (527 serological samples), we used the agarose gel immunodiffusion serological test (IDGA) to diagnose the EBL and characterize the risk factors through the application of epidemiological questionnaires. We used the logistic regression test to evaluate the existence of a significant association between the variables. The EBL frequency in the study area was 14.42%. We detected seroreagent bovines in all municipalities evaluated with 95% of the properties showing outbreaks of the disease. The reuse of needles was the risk factor with the most significant statistical association (P < 0.01; OR = 2.16). Discussion: The origin of EBL in the Brazilian Amazon is probably related to the expansion of dairy cattle in the 1980s, which, at first, demanded the importation of cattle for the fast formation of the herds, without complying with the sanitary criteria of animal commercialization. The frequency of EBL in the Rio Branco microregion is below the estimated national average, as well as the regional level. The reduced influx of animals due to the geographical situation of Acre, since it is an area of greater physical isolation due to forest and river barriers, may influence the observed frequency. Different environmental conditions, herd size, cattle management, genetics and particularities of the diagnostic techniques should also be considered. The Rio Branco microregion can currently be considered as an area of medium frequency for BLV infection, a situation that ranges from 11 to 30% in the occurrence rate. When compared to herds with low infection frequency (<10%), the elimination of seroreagent animals and their respective outbreaks become more expensive in areas of medium or high frequency. As for the number of outbreaks detected, the finding reflects the degree of negligence regarding the prophylactic measures of EBL since it is a silent propagation disease, as well as the implications for the absence of official control and eradication programs in Brazil. According to the final logistic regression model, the reuse of needles for vaccinations, deworming, and for applying other drugs in different animals was the risk factor of greater association in the region, explaining the widespread occurrence of EBL in the studied farms. In Canadian herds, this practice also was associated with an increase in clinical cases. It is known that ...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Risk Factors for Enzootic Leukosis in Dairy Cattle from the Brazilian Amazon

Silva

Melchior

Reckziegel

et al. 2019

Acta Scientiae. Vet.

View full text Add to dashboard Cite

show abstract

“…Otra posible vía de transmisión horizontal del BLV es a través de insectos hematófagos, que pueden actuar como vectores mecánicos, especialmente en zonas de climas cálidos (Ohshima et al, 1981). Este tipo de transmisión depende de la densidad de insectos, de la proporción de animales infectados y del nivel de la carga proviral en los animales (Foil et al, 1988;Kohara et al, 2018). Esto explicaría que durante los meses de verano, coincidente con una mayor densidad de insectos hematófagos, se produce el contagio de la enfermedad en establecimientos donde se aplican medidas de higiene estrictas en las maniobras de manejo animal, tanto entre animales criados a campo como en estaca o en corrales contiguos (Kobayashi et al, 2014(Kobayashi et al, , 2015.…”

Section: Transmisiónunclassified

“…La aplicación de estas medidas en rodeos donde conviven animales infectados con animales libres de BLV requiere de una minuciosa y estricta sistematización del manejo animal y, aun así, la eficacia de este enfoque puede verse socavada por factores humanos y ambientales. Como medidas adicionales a las ya descritas, se recomienda aplicar conjuntamente programas de control de vectores hematófagos, como aplicación de pesticidas sobre los animales o colocación de mallas mosquiteras en los establos donde habitan los bovinos (Ooshiro et al, 2013;Kohara et al, 2018). Se recomienda además, ordeñar las vacas infectadas al final de cada ordeñe, especialmente los animales con ACP.…”

Section: Estrategias Tradicionalesunclassified

Leucosis bovina

Gutiérrez¹,

Lützelschwab²,

Barrios³

et al. 2020

Rev. investig. vet. Perú

View full text Add to dashboard Cite

La leucosis bovina enzoótica, causada por el virus de la leucosis bovina (BLV), es la enfermedad tumoral más frecuente del bovino. Las razas bovinas de leche y de carne son susceptibles a la infección por BLV y al linfosarcoma; sin embargo la enfermedad es más prevalente en rodeos lecheros, principalmente debido a las prácticas de manejo. La patogenicidad del BLV en el bovino está asociada a la genética del animal. La mayoría de los bovinos infectados por el BLV son asintomáticos, por lo que la infección puede pasar desapercibida cuando los índices de infección son relativamente bajos. En ausencia de medidas de control, el virus se disemina lentamente entre los animales del rodeo. El BLV causa importantes pérdidas productivas, no sólo debido a la mortandad de animales con linfosarcoma, sino también por las restricciones al comercio de animales infectados y sus subproductos. Existen distintas alternativas para el control del BLV, adecuadas para distintas situaciones epidemiológicas. Hasta el momento no existe ningún tratamiento o vacuna eficaz para el control de este virus. Cuando la prevalencia de infección es baja, inferior al 10-15% de animales infectados, se recomienda identificar y eliminar la totalidad de los animales infectados. Esta alternativa no se adecúa a rodeos con altas prevalencias de infección, como ocurre con la mayoría de los rodeos lecheros en Argentina. La selección genética de animales resistentes a la diseminación del BLV surge como una estrategia natural para limitar la diseminación de este virus y, por ende, para el control del linfosarcoma asociado.

show abstract

“…Insect vectors such as tabanids and other large biting flies also may transmit the virus. However, their role as vectors of BLV under a natural grazing system is still a matter for discussion (3,4).…”

Section: Introductionmentioning

confidence: 99%

Sero-Prevalence of Bovine Leukemia Virus Infection in Kosovo Cattle

Gjinovci¹,

Cana

Alishani

et al. 2020

Macedonian Veterinary Review

View full text Add to dashboard Cite

A cross-sectional survey was conducted in Kosovo to determine the presence and prevalence of bovine leukemia virus antibodies in cattle. A total of 5,051 serum samples from 315 villages were collected during 2016. Samples were tested using commercial indirect enzyme-linked immunosorbent assay. At least one sero-positive animal was found in 55 (17.5%) of the villages sampled, of which 23 had more than one sero-positive detected. Overall individual sero-prevalence, corrected for geographic distribution of samples, was found to be 2.26% (95% c.i. 1.62% to 3.04%). There were no statistically significant associations between serological status and herd size or age of animal, although sero-prevalence in 5-year-old cattle was higher than in the other ages. There was a statistical significant heterogeneity in sero-prevalence between different geographic zones of Kosovo (chi-square value = 20.68 (4 d.f.); (p=0.0004). Pairwise comparisons showed that sero-prevalence in the south was significantly higher than in the east and in the north and sero-prevalence in the west was significantly higher than in the north. The 3.11% aggregated sero-prevalence for the two highest sero-prevalence zones, south and west, was significantly higher than the 1.57% aggregated sero-prevalence for the remaining zones, centre, east and north (Fisher exact p-value (2-tail) = 0.0004). The reason for higher prevalence in the south and west of Kosovo is uncertain. These results may serve to enrich the information of bovine leukemia virus distribution in the region, as well as a starting point for the future control and eradication strategy in Kosovo.

show abstract

Vector control efficacy of fly nets on preventing bovine leukemia virus transmission

Cited by 26 publications

References 20 publications

Risk Factors for Enzootic Leukosis in Dairy Cattle from the Brazilian Amazon

Risk Factors for Enzootic Leukosis in Dairy Cattle from the Brazilian Amazon

Leucosis bovina

Sero-Prevalence of Bovine Leukemia Virus Infection in Kosovo Cattle

Contact Info

Product

Resources

About