Benoit Durand

A cross-sectional study was conducted on bovine brucellosis in a sample of 173 medium/small-scale cattle farmers in a tropical region of Ecuador. A total of 173 milk tank samples were collected and analyzed through an indirect ELISA. A survey was also applied to each farm to collect information on herd management, evaluate the level of knowledge about the disease and estimate the risk that bovine brucellosis on those farms could represent for public health. The apparent prevalence among farms was 11.5% (95% CI: 6.7%–16.2%). The medium farms had a prevalence significantly higher (23.8%, 95% CI: 10.9%–36.6%, p < 0.0001 ) than the small farms (7.6%, 95% CI: 4.5%–9%). Two multivariable analysis were conducted to identify risk factors associated with bovine brucellosis or reproductive disorders. Medium farms had 3.7 more odds to be infected than the small farms (OR: 3.7, 95% CI: 1.39–9.84, p = 0.008 ). Incineration/burial of abortion material was identified as a protective factor (OR: 0.4, 95% CI: 0.14–0.98, p = 0.04 ). Farm size and brucellosis were identified as risk factors for the occurrence of reproductive disorders. Only 25% of the farmers were aware of bovine brucellosis. Unpasteurized curdled milk was regularly consumed and marketed on 112 farms of which 14 were positive for bovine brucellosis. Highly at-risk practices, such as manipulation of aborted fetuses were also reported. These results indicate that there is a need to develop public health education programs targeted at medium/small-scale farmers in Ecuador.

Japanese encephalitis virus (JEV) is a vector-borne zoonotic virus and the leading cause of human acute encephalitis in Asia. Continuous human and commercial exchanges between Southeast Asia where JE is endemic and Reunion Island increase the risk of introducing JEV on the island, where putative vectors of JEV such as Culex quinquefasciatus and amplifying hosts such as pigs are present. Each of the 255 Reunionese pig farms was assumed to harbor a Cx. quinquefasciatus population and, together with the competent hosts: pigs and poultry and noncompetent hosts: humans, dogs, and cattle, located within a radius of 1 km, formed an epidemiological unit. We used a deterministic compartmental model to investigate whether these epidemiological units could be invaded by JEV in the event of an introduction. Since the vector population size changes seasonally, we computed the basic reproduction number (R0) using vector population sizes ranging from 100 to 100,000 vectors for each of the 255 epidemiological units. The size of the potentially exposed human population was calculated in the case where the virus would be introduced in a single epidemiological unit and in the extreme case where the virus would have spread over the whole island. For a vector population of 1,000 vectors per unit, 2 out of 255 units had an R0 ≥ 1. With 50,000 vectors per unit, more than 75% (193/255) of the units had an estimated R0 ≥ 1, representing a median of approximately 2,500 potentially exposed people if JEV was introduced in a single unit, and about 140,000 potentially exposed people if JEV had expanded throughout the island. The unit located a few kilometers from the large port area of Reunion Island had an estimated R0 ≥ 1 with at least 10,000 vectors, making it a potential gateway to JEV given a virus introduction of infected vectors.