RESUMO
African swine fever virus (ASFV) is the etiological agent of African swine fever (ASF), a disease of domestic and wild swine that has spread throughout a large geographical area including Central Europe, East and Southeast Asia, and Southern Africa. Typically, the clinical presentation of the disease in affected swine heavily depends on the virulence of the ASFV strain. Very recently, ASFV was detected in the Dominican Republic (DR) and Haiti, constituting the first diagnosis of ASFV in more than 40 years in the Western hemisphere. In this report, the clinical presentation of the disease in domestic pigs inoculated with an ASFV field strain isolated from samples collected in the DR (ASFV-DR21) was observed. Two groups of domestic pigs were inoculated either intramuscularly (IM) or oronasally (ON) with ASFV-DR21 (104 hemadsorbing dose-50% (HAD50)). A group of naïve pigs (designated as the contact group) was co-housed with the ASFV-DR21 IM-inoculated animals to evaluate ASFV transmission and disease manifestation. Animals inoculated IM with ASFV-DR21 developed an acute disease leading to humane euthanasia at approximately day 7 post-inoculation (pi). Interestingly, animals inoculated via the ON route with ASFV-DR21 developed a heterogeneous pattern of disease kinetics. One animal developed an acute form of the disease and was euthanized on day 7 pi, another animal experienced a protracted presentation of the disease with euthanasia by day 16 pi, and the remaining two animals presented a milder form of the disease, surviving through the 28-day observational period. The contact animals also presented with a heterogenous presentation of the disease. Three of the animals presented protracted but severe forms of the disease being euthanized at days 14, 15 and 21 pi. The other two animals presented with a milder form of the disease, surviving the entire observational period. In general, virus titers in the blood of animals in all study groups closely followed the clinical presentation of the disease, both in length and extent. Importantly, all animals presenting with a prolonged form of the disease, as well as those surviving throughout the observational period, developed a strong ASFV-specific antibody response. These results suggest that ASFV-DR21, unless inoculated parenterally, produces a spectrum of clinical disease, with some animals experiencing an acute fatal form while others presented with a mild transient disease accompanied by the induction of a strong antibody response. At the time of publication, this is the first report characterizing the virulent phenotype of an ASFV field strain isolated from samples collected in the DR during the 2021 outbreak and provides information that may be used in developing epidemiological management measures to control ASF on the island of Hispaniola.
Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Vírus da Febre Suína Africana/genética , Animais , República Dominicana , Sus scrofa , Suínos , Virulência/genéticaRESUMO
Pork accounts for almost one-third of the meat consumed worldwide. Infectious diseases have a marked impact on pig production. Epidemiological indicators are considered the most useful criteria in decision-making; however, a health status assessment remains a challenge at the national and regional levels. This study proposes a health index including herd-losses, morbidity, fatality, and type of diseases, to rate the health situation in a region or country; it contributes to assessing the effectiveness of control, damage manifestation, and trends. It is a multidimensional index with a structure of triads and simple quantitative, semi-quantitative, and qualitative expressions that use flexible and dynamics limits. With it, we analyzed twenty-one countries in 2005-2018, focusing on African swine fever, classical swine fever, foot-mouth-disease, and porcine respiratory and reproductive syndrome, diseases that caused 72% of the morbidity. Our multidimensional approach estimates farm, local, and regional impact from infectious agents and outbreaks, and apprises trends aiming to be useful to control measures, strategic actions, and animal health policies.