Reproduction of contagious bovine pleuropneumonia via aerosol-based challenge with Mycoplasma mycoides subsp. mycoides

Abstract

Contagious bovine pleuropneumonia (CBPP) is a respiratory disease caused by Mycoplasma mycoides subsp. mycoides. Infection occurs via Mycoplasma-containing droplets and therefore requires close contact between animals. The current infection models are suboptimal and based on intratracheal installation of mycoplasmas or in-contact infection. This work tested the infection of adult cattle via aerosols containing live mycoplasmas mimicking the infection of cattle in the field. Therefore, we infected six cattle with aerosolized Mycoplasma mycoides subsp. mycoides strain Afadé over seven consecutive days with altogether 109 colony forming units. All animals seroconverted between 11–24 days post infection and five out of six animals showed typical CBPP lesions. One animal did not show any lung lesions at necropsy, while another animal had to be euthanized at 25 days post infection because it reached endpoint criteria. Seroconversion confirmed successful infection and the spectrum of clinical and lesions observed mirrors epidemiological models and the field situation, in which only a fraction of animals suffers from acute clinical disease post infection.

Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences

“…Well characterized animal models must demonstrate that disease in the model is well understood and be used to adequately show efficacy and efficacy endpoints that are related to outcomes in the natural host (e.g., increased survival). Developing such models relies on characterizing a specific agent (e.g., species or strain), a relevant route and target dose, and appropriate disease outcomes that recapitulate natural disease [291,655,656]. In many cases for TADs, research design varies between facilities and standard models have not been developed.…”

“…Mice develop mycoplasmaemia following infection, but they are not a good model of the pathology seen in CBPP [285,288]. Cattle models are costly and can present difficulties reproducing disease, but several challenge techniques have been developed [240,241,[288][289][290][291]. Contact infection studies resemble natural infection but require an extra group of diseased animals and result in an unpredictable rate and timing of transmission, making it difficult to compare disease outcomes [290,291].…”

“…Cattle models are costly and can present difficulties reproducing disease, but several challenge techniques have been developed [240,241,[288][289][290][291]. Contact infection studies resemble natural infection but require an extra group of diseased animals and result in an unpredictable rate and timing of transmission, making it difficult to compare disease outcomes [290,291]. Endobronchial inoculation of three different strains of Mmm in steers showed two strains (Ondangwa and Shawawa) may be useful for study of subacute and chronic infections, while the third (Gladysdale) more closely mimics the peracute form of disease [289].…”

“…Nkando et al presented nasotracheal inoculation of cattle with the aid of a bronchoscope as an alternative to an endobronchial intubation approach where tube insertion requires sedation of the animal [290]. Repeated aerosol nasal infection of cattle has been reported to closely mirror natural epidemiology in which only a fraction of animals develops acute disease [291]. This approach avoids "overchallenge" that could be seen with direct tracheal or bronchial instillation [291].…”

“…Repeated aerosol nasal infection of cattle has been reported to closely mirror natural epidemiology in which only a fraction of animals develops acute disease [291]. This approach avoids "overchallenge" that could be seen with direct tracheal or bronchial instillation [291].…”