Brucella species circulating in rural and periurban dairy cattle farms: a comparative study in an endemic area.

Brucellosis is among the most important zoonotic infectious diseases worldwide affecting both humans and domestic animals. The present study aimed to determine and compare the seroprevalence of brucellosis among rural and periurban dairy cattle farms of four Iranian provinces from 2017 to 2019. We applied different serological tests, including RBT, SAT, and iELISA to evaluate the brucellosis prevalence among 2808 dairy cattle. Species-specific multiplex PCR and biotyping tests were also used to further identify the implicated Brucella species. Serological screening using RBT, SAT, and iELISA led to 157 (5.6%), 112 (3.9%), and 139 (4.9%) positive results among tested cattle, respectively. Brucella abortus biovars 1 (2 cases) and biovars 3 (42 cases) were identified by biotyping experiments and multiplex PCR in all 44 tested lymph node samples. Further, Cohen's kappa statistical analysis revealed that the best degree of agreement was seen between RBT and iELISA (99.4%), followed by SAT/iELISA (98.5%) and finally RBT/SAT (98.4%). Our results also showed a significantly lower seroprevalence of brucellosis in periurban dairy cattle when compared to rural dairy cattle population (p value= 0.01). These results reflect the need for better vaccine coverage using RB51 combined with an appropriate test-and-slaughter program in the rural dairy cattle population.

Morbidity Rates in an Area with High Livestock Density: A Registry-Based Study Including Different Groups of Patients with Respiratory Health Problems.

There is continuing debate and public health concern regarding the previously confirmed association between high livestock density and human health. The primary aim of the current study is to assess the prevalence of respiratory and other health problems in a livestock dense area in the Netherlands, based on recent longitudinal health data and a large sample. Analyses are expanded with the investigation of different subgroups of patients with respiratory health problems and the inclusion of various chronic and acute health outcomes, as well as prescribed medication. Prevalence of health symptoms and chronic conditions was assessed for the period 2014-2016, based on electronic health records registered in 26 general practices located in areas with intensive livestock farming in the Netherlands ("livestock dense area", n = 117,459 unique residents in total). These were compared with corresponding health data from general practices (n = 22) in different rural regions with a low density of livestock farms or other major environmental exposures ("control area", n = 85,796 unique residents in total). Multilevel regression models showed a significantly higher prevalence of pneumonia in the total sample in the livestock dense area, which was also observed among susceptible subgroups of children, the elderly, and patients with chronic obstructive pulmonary disease (COPD). Lower respiratory tract infections, respiratory symptoms, vertigo, and depression were also more common in the livestock dense area compared to the control area. In general, there were no significant differences in chronic conditions such as asthma, COPD, or lung cancer. Prescription rates for broad-spectrum antibiotics were more common among patients with pneumonia in the livestock dense area. Acute respiratory infections and symptoms, but not chronic conditions, were considerably more common in areas with a high livestock density. Identification of causal pathogens on the basis of serological analyses could further elucidate the underlying mechanisms behind the observed health effects.