Transmission Dynamics Of Brucellosis Research Articles

Transmission dynamics of brucellosis in Jilin province, China: Effects of different control measures

Brucellosis is a zoonotic disease, which has gave rise to massive financial burden to animal husbandry in China. Jilin province is one of the worst-hit areas of brucellosis and thus understanding the transmission mechanism of brucellosis is of great significance for successful containment. In this paper, we leverage a discrete-time human-sheep coupled model constructed by employing backward Euler method to investigate the effects of different control measures on the brucellosis transmission in Jilin province. Firstly, we introduce the basic reproduction number R0 which completely determines the threshold dynamics. Secondly, the parameters values of the transmission dynamics are estimated based on the confirmed human brucellosis cases and the trend of newly infected human brucellosis cases are simulated for the next few years in Jilin province, and the simulated results elucidate that brucellosis will not disappear in a short time. Lastly, we reveal that enlarging the frequency and effectiveness of disinfection, the efficacy of propaganda and education, and the elimination rate can reduce the prevalent time and final scale of brucellosis in Jilin Province. Specifically speaking, when the disinfection frequency τ=0.0666 and the effective disinfection rate δ=0.3, the incidence of brucellosis can be dropped to less than 1 per 100,000 eleven years ahead of baseline model. When the effectiveness of propaganda and education is 60%, the control target will be attained eight years in advance. When the elimination rate μ increases by 20%, brucellosis can reach the control target ten years ahead. However, when the new born number of sheep exceeds 12075 or the elimination rate is below 0.00234, the brucellosis will outbreak promptly. Overall, the obtained results may be conductive to suppress the spread of brucellosis.

Stationary Distribution and Extinction of a Stochastic Brucellosis Model with Standard Incidence

In this paper, we proposed a stochastic SVEI brucellosis model with stage structure by introducing the effect of environmental white noise on transmission dynamics of brucellosis. By Has'minskii theory and constructing suitable Lyapunov functions, we established sufficient conditions on the existence of ergodic stationary distribution for the considered model. Moreover, we also established sufficient condition for extinction of the disease. Finally, two examples with numerical simulations are given to illustrate the main results of this paper.

Transmission dynamics of brucellosis with patch model: Shanxi and Hebei Provinces as cases.

Brucellosis is a zoonotic disease caused by Brucella, and it is an important infectious disease all over the world. The prevalence of brucellosis in the Chinese mainland has some spatial characteristics besides the temporal trend in recent years. Due to the large-scale breeding of sheep and the frequent transportation of sheep in various regions, brucellosis spreads wantonly in pastoral areas, and human brucellosis spreads from traditional pastoral areas and semi-pastoral areas in the north to non-pastoral areas with low incidence in the south. In order to study the influence of sheep immigration on the epidemic transmission, a patch dynamics model was established. In each patch, the sub-model was composed of humans, sheep and Brucella. The basic reproduction number, disease-free equilibrium and positive equilibrium of the model were discussed. On the other hand, taking Shanxi Province and Hebei Province as examples, we carried out numerical simulations. The results show that the basic reproduction numbers of Shanxi Province and Hebei Province are 0.7497 and 0.5022, respectively, which indicates that the current brucellosis in the two regions has been effectively controlled. To reduce brucellosis faster in the two provinces, there should be a certain degree of sheep immigration from high-infection area to low-infection areas, and reduce the immigration of sheep from low-infection areas to high-infection areas.

Sero-epidemiology and associated risk factors of brucellosis among sheep and goat population in the south western Nepal: a comparative study

BackgroundBrucellosis is a zoonotic disease caused by Brucella spp. In Nepal, the presence of brucellosis in small ruminants, namely sheep and goats, has impacted farmers’ livelihood and the food safety of consumers. A cross-sectional study was conducted in Rupandehi district of Nepal during January to March 2020 to investigate the seroepidemiology and associated risk factors of brucellosis in the sheep and goat population. Altogether, 19 sheep and 60 goat farms in the district were visited. Owners were interviewed to get information on animals, including their management and movement patterns. Three hundred fifty-seven samples (80 sheep and 277 goat samples) were collected proportionately based on farm sizes. Each serum sample was tested with Rose Bengal Test and ELISA to estimate the seropositivity of brucellosis. Logistic regression was carried out to calculate corresponding odds ratios of each variable associated with detection of brucellosis.ResultsAt the farm level, 31.6% (6/19; 95% CI: 12, 54%) of sheep farms and 3.3% (2/60, 95% CI: 0.9, 11.4%) of goat farms were seropositive to brucellosis. Out of 80 sheep serum samples, 12 (15%; 95% CI: 8.79–24.41%) and out of 277 goat serum samples, three (1.1%; 95% CI: 0.37–3.14%) were seropositive to brucellosis. Age greater than 1.5 years (OR = 5.56, 95% CI: 1.39, 29.38; p = 0.02) and herd size of greater than 100 (OR = 4.74, 95% CI: 1.23, 20.32, p = 0.03) were identified as significant risk factors for seropositivity of brucellosis in the sheep population. While in the goat population, none of the variables was identified as a significant risk factor.ConclusionThe study provides evidence that the older sheep and the sheep from the large herds were at higher risk of brucellosis. A control program should be put in place immediately in the sheep population because they may transmit infections to other livestock as they were regularly moved for grazing and selling purposes. Also, strict biosecurity measures should be implemented among pastoralists to prevent brucellosis transmission in them. We suggest further one health-based study to reveal the transmission dynamics of brucellosis between animals and humans.

Modeling the Impact of Seasonal Weather Variations on the Infectiology of Brucellosis.

A deterministic mathematical model for brucellosis that incorporates seasonality on direct and indirect transmission parameters for domestic ruminants, wild animals, humans, and the environment was formulated and analyzed in this paper. Both analytical and numerical simulations are presented. From this study, the findings show that variations in seasonal weather have the great impact on the transmission dynamics of brucellosis in humans, livestock, and wild animals. Thus, in order for the disease to be controlled or eliminated, measures should be timely implemented upon the fluctuation in the transmission of the disease.

Optimal Control Strategies for the Infectiology of Brucellosis

Brucellosis is a zoonotic infection caused by Gram-negative bacteria of genus Brucella. The disease is of public health, veterinary, and economic significance in most of the developed and developing countries. Direct contact between susceptible and infective animals or their contaminated products are the two major routes of the disease transmission. In this paper, we investigate the impacts of controls of livestock vaccination, gradual culling through slaughter of seropositive cattle and small ruminants, environmental hygiene and sanitation, and personal protection in humans on the transmission dynamics of Brucellosis. The necessary conditions for an optimal control problem are rigorously analyzed using Pontryagin’s maximum principle. The main ambition is to minimize the spread of brucellosis disease in the community as well as the costs of control strategies. Findings showed that the effective use of livestock vaccination, gradual culling through slaughter of seropositive cattle and small ruminants, environmental hygiene and sanitation, and personal protection in humans have a significant impact in minimizing the disease spread in livestock and human populations. Moreover, cost-effectiveness analysis of the controls showed that the combination of livestock vaccination, gradual culling through slaughter, environmental sanitation, and personal protection in humans has high impact and lower cost of prevention.

Nontrivial periodic solution for a stochastic brucellosis model with application to Xinjiang, China

Brucellosis is a kind of zoonotic disease caused by Gram-negative bacteria of the genus Brucella. In this paper, we propose a stochastic periodic brucellosis model by introducing the effect of environmental white noise on transmission dynamics of brucellosis. By Has’minskii theory of periodic solution and constructing a novel combination of Lyapunov functions, we establish the existence of nontrivial positive periodic solution if the condition R0S>1 holds. Based on the reported data of newly acute human brucellosis cases for each season from 2010 to 2014 in Xinjiang, numerical simulations have been performed to support our result and indicate that brucellosis in Xinjiang takes on the feature of long-term prevalence and cyclical fluctuation.