RESUMEN
In 2006, epizootic haemorrhagic disease (EHD) outbreaks were recorded in the Maghreb (Tunisia, Morocco and Algeria) among cattle, resulting in severe repercussions on herds (oedema of the head, necrotic lesions of the oral mucosa, hyperthermia of the teats, accompanied by anorexia and respiratory distress) and economic losses. The present study gives new information on the molecular characterisation of the EHD virus (EHDV) that had circulated in Tunisia. Genome segments 2, 3, 6, 7 and 10 of EHDV, corresponding to the VP2, VP3, VP5, VP7 and NS3/NS3A proteins, respectively, were amplified from the blood of one animal by RT-PCR and sequenced. Nucleotide sequence comparisons of these five segments with sequences available in the GenBank demonstrated that an EHDV serotype 6 (EHDV-6) had been present in Tunisia in 2006. The possible origin of this strain is discussed.
Asunto(s)
Enfermedades de los Bovinos/virología , Brotes de Enfermedades/veterinaria , Virus de la Enfermedad Hemorrágica Epizoótica/genética , Infecciones por Reoviridae/veterinaria , Animales , Bovinos , Enfermedades de los Bovinos/epidemiología , Virus de la Enfermedad Hemorrágica Epizoótica/aislamiento & purificación , Filogenia , Infecciones por Reoviridae/epidemiología , Infecciones por Reoviridae/virología , Túnez/epidemiologíaRESUMEN
Two inbred mouse strains, derived from feral founders, are susceptible to experimental leishmaniasis due to Leishmania major and support a disease of a severity intermediate between those observed in strains C57BL/6 and BALB/c. Mice of the MAI strain develop a severe, nonhealing, but nonfatal disease with no resistance to a secondary parasite challenge. The immunological responses showed a TH2 dominance characterized by an early peak of interleukin-4 (IL-4) and IL-13. However, neutralization of IL-4, which leads to a resistance phenotype in BALB/c mice, has no effect on disease progression in MAI mice. Mice of strain PWK develop a protracted but self-healing disease, characterized by a mixed TH1-plus-TH2 pattern of immune responses in which IL-10 plays an aggravating role, and acquire resistance to a secondary challenge. These features are close to those observed in human cutaneous leishmaniasis due to L. major and make PWK mice a suitable model for the human disease.