Mathematical modelling and control of African animal trypanosomosis with interacting populations in West Africa—Could biting flies be important in main taining the disease endemicity?

Abstract

African animal trypanosomosis (AAT) is transmitted cyclically by tsetse flies and mechanically by biting flies (tabanids and stomoxyines) in West Africa. AAT caused by Trypanosoma congolense, T. vivax and T. brucei brucei is a major threat to the cattle industry. A mathematical model involving three vertebrate hosts (cattle, small ruminants and wildlife) and three vector flies (Tsetse flies, tabanids and stomoxyines) was described to identify elimination strategies. The basic reproduction number (R0) was obtained with respect to the growth rate of infected wildlife (reservoir hosts) present around the susceptible population using a next generation matrix technique. With the aid of suitable Lyapunov functions, stability analyses of disease-free and endemic equilibria were established. Simulation of the predictive model was presented by solving the system of ordinary differential equations to explore the behaviour of the model. An operational area in southwest Nigeria was simulated using generated pertinent data. The R0 < 1 in the formulated model indicates the elimination of AAT. The comprehensive use of insecticide treated targets and insecticide treated cattle (ITT/ITC) affected the feeding tsetse and other biting flies resulting in R0 < 1. The insecticide type, application timing and method, expertise and environmental conditions could affect the model stability. In areas with abundant biting flies and no tsetse flies, T. vivax showed R0 > 1 when infected wildlife hosts were present. High tsetse populations revealed R0 <1 for T. vivax when ITT and ITC were administered, either individually or together. Elimination of the transmitting vectors of AAT could cost a total of US$ 1,056,990 in southwest Nigeria. Hence, AAT in West Africa can only be controlled by strategically applying insecticides targeting all transmitting vectors, appropriate use of trypanocides, and institutionalising an appropriate barrier between the domestic and sylvatic areas.

Trypanosoma brucei Lipophosphoglycan Induces the Formation of Neutrophil Extracellular Traps and Reactive Oxygen Species Burst via Toll-Like Receptor 2, Toll-Like Receptor 4, and c-Jun N-Terminal Kinase Activation

“…Trypanosoma brucei brucei , a subspecies of the genus T. brucei , infects a variety of animals in Africa and causes widespread epidemics of African animal trypanosomosis (also known as trypanosomiasis or Nagana; Guerrini and Bouyer, 2007 ; Latif et al, 2019 ; Odeniran et al, 2020 ). African animal trypanosomiasis is transmitted by tsetse flies into the hosts during blood-sucking and the infected animals suffer from wasting, anemia, neurological symptoms, and even death ( Osaer et al, 1999 ; Diarra et al, 2019 ).…”

Mathematical modeling at the livestock-wildlife interface: scoping review of drivers of disease transmission between species

“…The majority of models used the same frameworks for both the domestic and wildlife populations, though five articles used different model frameworks for each species. Here, network models for domestic species were used in combination with a wildlife metapopulation model ( 49 ) or PBM ( 50 ), or domestic IBMs were used with a wildlife metapopulation model ( 51 ) or wildlife PBMs ( 39 , 52 ).…”

Parasite co-infection: an ecological, molecular and experimental perspective

“…The predicted effects of different strategies to control animal African trypanosomiasis (AAT) were also recently explored using modelling approaches. These data indicated that insecticidal treatment of cattle alone could eliminate T. brucei from the local population, but that it would have little effect on two other species, namely T. congolense and T. vivax , which are maintained in reservoirs such as wildlife and small ruminants [ 90 ].…”