Spatiotemporal distribution and temporal trends of brucellosis and tuberculosis in water buffalo (Bubalus bubalis) in Brazil

Cross-border surveillance of sheep and goat rabies in Brazil

Since Brazil has the largest territory in South America and borders 10 other countries, rabies control is strategic to prevent cross-border spread. However, prevention and control of rabies in small ruminants is neglected. The present study evaluated the spatiotemporal distribution and temporal trends of rabies in small ruminants in Brazil between 2005 and 2023. Official data on rabies case notifications and the population density of goats and sheep from the Brazilian states were used. Descriptive epidemiology and temporal analyses of high-risk clusters and trends were conducted. Rabies cases were reported in all states, except for the Federal District, Roraima, Amapá, Amazonas, and Rondônia. In sheep, 174 cases were reported, with an emphasis on Paraná (25.29 %), being highest. There were 64 cases in goats, with a highlight on Bahia (37.50 %) and Maranhão (18.75 %). However, Espírito Santo presented the highest incidence risk (IR) for goats and sheep. The highest peaks in IR occurred in 2005, 2006 and 2013. A temporal trend of decreasing goat cases was observed in northeastern Brazil from 2005 to 2023. In sheep, the Northeast region showed a downward trend in rabies cases. Three high-risk clusters were identified: the primary cluster for goats occurred in 2006, and for sheep, between 2005 and 2013. Rabies in small ruminants occurs across all Brazilian regions, with high-risk areas in the Northeast, Southeast, and South, as well as a risk of cross-border transmission. These findings support animal health authorities in strengthening rabies control for small ruminants and reducing the risk of transboundary spread.

Spread analysis of glanders in the state of Piauí, northeastern Brazil

Brazil is strategic in controlling neglected zoonoses, such as glanders, in its territory. Among the Brazilian states, Piauí is a strategic state for the spread of the disease in the country. The present study aimed to evaluate the spatial and temporal distribution of official cases of glanders in Piauí between 2015 and 2022. The glanders cases were located in the municipalities of the north and central-north mesoregions, mainly in Campo Maior, Teresina and Altos. The highest incidence risk (IR) occurred in of Altos (IR = 257.9), Sussuapara (IR = 158.4), and Teresina (IR = 157.7). A primary cluster was formed with a relative risk of 14.88 between 2019 and 2022, encompassing 34 municipalities in the north and central-north regions. In Piauí, glanders is well localized, with the potential for spread across borders. This is the first study demonstrating the distribution of reported cases of glanders in the state of Piauí.

High-Risk Regions of African Swine Fever Infection in Mozambique

African swine fever (ASF) is a transboundary infectious disease that can infect wild and domestic swine and requires enhanced surveillance between countries. In Mozambique, ASF has been reported across the country, spreading between provinces, mainly through the movement of pigs and their by-products. Subsequently, pigs from bordering countries were at risk of exposure. This study evaluated the spatiotemporal distribution and temporal trends of ASF in swine in Mozambique between 2000 and 2020. During this period, 28,624 cases of ASF were reported across three regions of the country. In total, the northern, central, and southern regions presented 64.9, 17.8, and 17.3% of the total cases, respectively. When analyzing the incidence risk (IR) of ASF per 100,000 pigs, the Cabo Delgado province had the highest IR (17,301.1), followed by the Maputo province (8868.6). In the space-time analysis, three clusters were formed in each region: (i) Cluster A involved the provinces of Cabo Delgado and Nampula (north), (ii) Cluster B involved the province of Maputo and the city of Maputo (south), and (iii) Cluster C consisted of the provinces of Manica and Sofala (central) in 2006. However, when analyzing the temporal trend in the provinces, most were found to be decreasing, except for Sofala, Inhambane, and Maputo, which had a stationary trend. To the best of our knowledge, this is the first study to evaluate the spatial distribution of ASF in Mozambique. These findings will contribute to increasing official ASF control programs by identifying high-risk areas and raising awareness of the importance of controlling the borders between provinces and countries to prevent their spread to other regions of the world.

Flow cytometric detection of IFN-γ production and Caspase-3 activation in CD4+ T lymphocytes to discriminate between healthy and Mycobacterium bovis naturally infected water buffaloes

Tuberculosis has a negative economic impact on buffalo farming, and it poses a potential threat to human health. Interferon-gamma (IFN-γ) plays a central role in protection against mycobacterial diseases, illustrating the importance of T-cell mediated immune responses in tuberculosis infection. Recently, the expression of Caspase-3, a critical executor of apoptosis, in M. tuberculosis-specific IFN-γ⁺CD4⁺ T cells was used as a new marker to distinguish active from latent tuberculosis infection in humans. The aims of this work were to develop a whole blood flow cytometric assay to detect the production of IFN-γ and the activation of Caspase-3 by CD4⁺ T lymphocytes from water buffalo and to evaluate whether these parameters can discriminate between healthy and M. bovis naturally infected buffaloes. A total of 35 Italian Mediterranean buffaloes were grouped in two groups: uninfected and M. bovis infected (based on the results of antemortem diagnostic tests: single intradermal tuberculin (SIT) and ELISA IFN-γ tests). Whole blood was incubated for 6 h with tubercular antigens: PPD-B, PPD-A, ESAT-6/CFP-10 and a new mix of precocious secreted antigens (PA). Our results showed a significant increase in the percentage of IFN-γ⁺CD4⁺ T cells in infected compared to the uninfected animals after each stimulus. Improved sensitivity of the assay was obtained by including the stimulation with the new mix of PA. Interestingly, we observed a concomitant decrease in percentage of Caspase-3⁺CD4⁺ T cells in M. bovis infected animals compared to the control healthy ones, regardless of the stimulus used. Overall, these results showed that M. bovis infection activates CD4⁺ T lymphocytes to produce IFN-γ and at the same time causes a concomitant decrease of Caspase-3 activation in CD4⁺ T cells. This study for the first time in water buffalo describes the development of a whole blood flow cytometric assay for the detection of IFN-γ producing CD4⁺ T cells and proposes the expression of active Caspase-3 as an additional bovine TB biomarker. Although further studies are needed to better understand the mechanisms of Caspase-3-mediated cell death during tuberculosis, our data can help to better understand the cellular immune response to M. bovis infection in buffalo species.

Geographical and temporal spread of equine rabies in Brazil

In Brazil, the horse is frequently used in cultural activities, sports, and in rural and urban work, implementing the economy in different social classes. Among the diseases in horses with zoonotic potential, rabies has been neglected in the country, increasing the risk of spreading the disease across borders. The present study evaluated the spatiotemporal distribution and temporal trend of rabies in horses in Brazil between 2010 and 2019. During this period, 1290 cases of rabies were detected in horses in Brazil, mainly in the states of São Paulo (21.7%) and Mato Grosso (13.3%). However, Espírito Santo stood out, with an incidence risk (IR) of 139.7 cases of rabies per 100,000 horses. The years 2013 and 2017 had higher peaks of IR for the disease, and the states that contributed to this increase were Mato Grosso, São Paulo, and Espírito Santo. There was no monthly seasonality of the disease among the states. The temporal trend revealed an increase for the northeastern region (Annual Percentage Change [APC]: 8.9%) and for Alagoas State (APC: 26.6%). In the spatiotemporal analysis, three high-risk clusters were formed: (i) cluster A (Relative Risk [RRs]: 6.21), involving only Minas Gerais, between 2017 and 2019; (ii) cluster B (RRs: 6.18), involving only Mato Grosso, between 2011 and 2013; and (iii) cluster C (RRs:4.71), involving the states of Rio de Janeiro and Espírito Santo, between 2010 and 2014. Only the states of Roraima and Amapá had no cases of equine rabies during the study period. Therefore, rabies in horses occurs in all Brazilian regions, with areas at high risk of infection concentrated in the Southeast. However, attention should be directed to the north-eastern and northern states, where notifications were infrequent, with an unknown risk in relation to the spread of rabies to transboundary regions. This is the first study evaluating the interstate distribution of rabies in equine species in regions of Brazil.