Transmission dynamics and elimination potential of zoonotic tuberculosis in morocco

Abstract

Bovine tuberculosis (BTB) is an endemic zoonosis in Morocco caused by Mycobacterium bovis, which infects many domestic animals and is transmitted to humans through consumption of raw milk or from contact with infected animals. The prevalence of BTB in Moroccan cattle is estimated at 18%, and 33% at the individual and the herd level respectively, but the human M. bovis burden needs further clarification. The current control strategy based on test and slaughter should be improved through local context adaptation taking into account a suitable compensation in order to reduce BTB prevalence in Morocco and decrease the disease burden in humans and animals. We established a simple compartmental deterministic mathematical model for BTB transmission in cattle and humans to provide a general understanding of BTB, in particular regarding transmission to humans. Differential equations were used to model the different pathways between the compartments for cattle and humans. Scenarios of test and slaughter were simulated to determine the effects of varying the proportion of tested animals (p) on the time to elimination of BTB (individual animal prevalence of less than one in a thousand) in cattle and humans. The time to freedom from disease ranged from 75 years for p = 20% to 12 years for p = 100%. For p > 60% the time to elimination was less than 20 years. The cumulated cost was largely stable: for p values higher than 40%, cost ranged from 1.47 to 1.60 billion euros with a time frame of 12 to 32 years to reach freedom from disease. The model simulations also suggest that using a 2mm cut off instead of a 4mm cut off in the Single Intradermal Comparative Cervical Tuberculin skin test (SICCT) would result in cheaper and quicker elimination programs. This analysis informs Moroccan bovine tuberculosis control policy regarding time frame, range of cost and levels of intervention. However, further research is needed to clarify the national human-bovine tuberculosis ratio in Morocco.

Molecular characterization of bovine tuberculosis strains in two slaughterhouses in Morocco

“…Overall, our findings reflect rather the epidemiological situation of a low level endemic transmission similar to other African countries rather than the one of a peri-urban intensive system [ 53 , 54 ]. More research is needed to further characterize the ongoing transmission patterns of bovine tuberculosis in view of the development of a locally adapted elimination strategy of bovine tuberculosis in Morocco [ 55 ].…”

A stochastic SIRI epidemic model with relapse and media coverage

“…Zoonotic tuberculosis in Morocco Zoonotic diseases play a very important role among human communicable diseases. In a review of more than 1400 pathogens known to infect humans, it was found that more than 61% where zoonotic [1]. Zoonotic diseases often serve as a starting point of many pathogens that jump the species barrier and became effectively transmissible human to human.…”

“…Zoonotic diseases often serve as a starting point of many pathogens that jump the species barrier and became effectively transmissible human to human. This example represents a simulation for transmission dynamic and elimination potential of zoonotic tuberculos in Morocco [1]. The average lifespan of the Moroccan cattle is 6 years which yields to a death rate of µ = 0.167.…”

Risk Factors for the Transmission of Mycobacterium Bovis to Slaughterhouses Workers in Brazzaville, Republic of the Congo

“…Transmission can also occur through prolonged exposure to bacteria in the air in the immediate vicinity of live infected cattle or their carcasses (17). On rare occasions, bovine TB is passed to a human when bacteria from the infected animal get into a cut on a person's skin (18).…”