Assessment of anthelmintic effectiveness to control Fasciola hepatica and paramphistome mixed infection in cattle in the humid tropics of Mexico.

The objective of this study was to evaluate the effectiveness of the main anthelmintics used for the control of trematodes in cattle in an endemic area in the humid Mexican tropics. A diagnostic study was carried out in nine cattle farms to determine the prevalence of flukes through faecal examination. Only three farms with more than 20 cows positive to trematodes were chosen to determine the effectiveness of commercial anthelmintics (triclabendazole, TCBZ; ivermectin + closantel, (IVM + CLOS); IVM + clorsulon, (CLORS); nitroxynil, NITROX). The prevalence of Fasciola hepatica was 27.1% and 29.6% of paramphistomes. The faecal egg count of trematodes ranged from 0.0 to 12.2 eggs per gram of faeces. The highest effectiveness against F. hepatica was 96.7%, and 92.7% against paramphistomes. NITROX was the most effective in the control of trematodes, while other products, such as IVM + CLORS and TCBZ obtained values lower than 90%, which puts sustainable trematode control at risk. The presence of trematodes was observed on most farms, although the prevalence per herd was highly variable, which indicates that the trematodes F. hepatica and paramphistomes are endemic to the region and a suitable management programme is suggested to control infections caused by these parasites.

Research on Integrated Management for Cattle Fever Ticks and Bovine Babesiosis in the United States and Mexico: Current Status and Opportunities for Binational Coordination.

Bovine babesiosis is a reportable transboundary animal disease caused by Babesia bovis and Babesiabigemina in the Americas where these apicomplexan protozoa are transmitted by the invasive cattle fever ticks Rhipicephalus (Boophilus) microplus and Rhipicephalus(Boophilus) annulatus. In countries like Mexico where cattle fever ticks remain endemic, bovine babesiosis is detrimental to cattle health and results in a significant economic cost to the livestock industry. These cattle disease vectors continue to threaten the U.S. cattle industry despite their elimination through efforts of the Cattle Fever Tick Eradication Program. Mexico and the U.S. share a common interest in managing cattle fever ticks through their economically important binational cattle trade. Here, we report the outcomes of a meeting where stakeholders from Mexico and the U.S. representing the livestock and pharmaceutical industry, regulatory agencies, and research institutions gathered to discuss research and knowledge gaps requiring attention to advance progressive management strategies for bovine babesiosis and cattle fever ticks. Research recommendations and other actionable activities reflect commitment among meeting participants to seize opportunities for collaborative efforts. Addressing these research gaps is expected to yield scientific knowledge benefitting the interdependent livestock industries of Mexico and the U.S. through its translation into enhanced biosecurity against the economic and animal health impacts of bovine babesiosis and cattle fever ticks.

Emerging strains of porcine epidemic diarrhoea virus (PEDv) in Mexico.

As an emerging disease, the porcine epidemic diarrhoea virus has caused substantial economic losses to the pork industry in Mexico, leading to piglet mortality rates of up to 100%. For detection, sequencing and genetic characterization of the virus, 68 samples of one-week-old piglets from pork farms in 17 states of Mexico were analysed. In total, 53 samples were positive by real-time RT-PCR, confirming the presence of the virus in 15 states. Twenty-eight samples from 10 states were amplified by endpoint RT-PCR, and 20 sequences of the spike gene were obtained. A phylogenetic analysis based on the spike gene demonstrated that all Mexican strains are in Group II and are classified as non-Indel-S emerging variants. Three strains showed amino acid insertions: PEDv/MEX/GTO/LI-DMZC15/2015 and PEDv/MEX/QRO/LI-DMZC45/2016 showed one amino acid insertion (424 Y425 and 447 D448 , respectively), and PEDv/MEX/QRO/LI-DMZC49/2019 showed one and two amino acid insertions (422 C423 and 537 SQ538 ), with the second insertion in the COE region. These results provide evidence of the prevalence of emerging, non-Indel-S strains of the virus are currently circulating in Mexico during 2016-2018, when three of which have amino acid insertions: PEDv/MEX/GTO/IN-DMZC15/2015 and PEDv/MEX/QRO/IN-DMZC45/2016 have one amino acid insertion each (424 Y425 and 447 D448 , respectively), and PEDv/MEX/QRO/IN-DMZC49/2019 has one (422 C423 ) and two amino acid insertions (537 SQ538 ), the latter being in the COE region, which could generate new antigenic variants.

Gray fox (Urocyon cinereoargenteus) parasite diversity in central Mexico.

Mexico has a long history of parasitological studies in communities of vertebrates. However, the mega diversity of the country makes fauna inventories an ongoing priority. Presently, there is little published on the parasite fauna of gray foxes (Urocyon cinereoargenteus Schereber, 1775) and this study provides new records of parasites for gray foxes in central Mexico. It is a continuation of a series of previous parasitological studies conducted with this carnivore in Mexico from 2003 to the present. A total of 24 foxes in the Parque Nacional El Cimatario (PANEC) were trapped, anaesthetized, and parasites recovered. The species found were Dirofilaria immitis, Ctenocephalides canis, C. felis, Euhoplopsillus glacialis affinis (first report for gray foxes in Mexico) Pulex simulants, and Ixodes sp. Three additional gray fox carcasses were necropsied and the parasites collected were adult nematodes Physaloptera praeputialis and Toxocara canis. The intensive study of the gray fox population selected for the 2013-2015 recent period allowed for a two-fold increase in the number of parasite species recorded for this carnivore since 2003 (nine to 18 parasite species), mainly recording parasitic arthropods, Dirofilaria immitis filariae and adult nematodes. The parasite species recorded are generalists that can survive in anthropic environments; which is characteristic of the present ecological scenario in central Mexico. The close proximity of the PANEC to the city of Santiago de Queretaro suggests possible parasite transmission between the foxes and domestic and feral dogs. Furthermore, packs of feral dogs in the PANEC might have altered habitat use by foxes, with possible impacts on transmission.

Evaluación de la Patogenicidad y Capacidad Protectora de un Inmungeno Fresco Combinado de Babesia Bigemina y Babesia Bovis / Evaluación of pathogenicity and protección capability of a fresh combined immunogen of Babesia bigemina and Babesia bovis

El objetivo del trabajo fue evaluar la inocuidad y la capacidad inmunoprotectora de un inmunógeno combinado de Babesia bigemina y Babesia bovis a una dosis de 108 y 109, respectivamente, bajo un desafío controlado. En el primer experimento (inocuidad) se utilizaron 16 bovinos Holstein provenientes de una zona libre de garrapatas y negativos a anticuerpos contra Babesia spp, mediante la prueba de inmunofluorescencia indirecta (IFI), los cuales fueron inoculados, vía intramuscular, con 1 X 109 eritrocitos infectados (EI) con una cepa atenuada de B. bigemina y 108 EI de una clona irradiada de B. bovis, ambas derivadas de cultivo in vitro. Se observaron cambios en las constantes fisiológicas a partir del día 7 y hasta el día 14 posinoculación (PI) en los animales sin verse éstos físicamente afectados. El porcentaje de eritrocitos parasitados (PEP) fue <0.01 por ciento. El segundo experimento (inmunogenicidad), se realizó tres meses PI y consistió en el desafío de 8 de los animales del experimento 1 con cepas virulentas de ambas especies del protozoario a una dosis de 108 EI de cada una. Cuatro animales adicionales sirvieron como grupo testigo. El grupo inmunizado presentó ligera disminución en el volumen celular aglomerado (VCA) con temperatura rectal (TR) sin cambios y PEP de 0.06 y <0.01 para B. bigemina y B. bovis, respectivamente. El grupo testigo presentó TR mayor a 400C, disminución del VCA (29 por ciento) y el PEP fue de 0.5 para B. bigemina y 0.03 para B. bovis; estos animales requirieron tratamiento para evitar su muerte. Se concluye que el inmunógeno combinado de B. bigemina y B. bovis a dosis altas no provoca reacciones clínicas severas en animales susceptibles y proporciona una sólida protección al desafío controlado con cepas virulentas