Danofloxacin (Advocin) reduces the spread of contagious bovine pleuropneumonia to healthy in-contact cattle

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most important diseases of cattle in Sub-Saharan Africa. The live T1/44 vaccine is normally used for its control but produces only transient protection and gives rise to adverse reactions. The present study evaluated the efficacy of danofloxacin (2.5% Advocintrade mark, Pfizer Ltd.) for the treatment of naturally infected cattle and in the prevention of CBPP transmission to in-contact cattle. Adult cattle, taken from a natural outbreak, were placed into two groups of 10 animals and kept on a research farm in paddocks 50m apart. One group was treated with 2.5mg/kg danofloxacin on days 0, 1 and 2; the other group were saline treated. On day 2, 10 CBPP-free, seronegative cattle were placed in contact with each of the two groups. All cattle were monitored for 3.5 months. No differences were seen in clinical improvement of the CBPP-affected cattle treated with danofloxacin compared with the untreated CBPP-affected cattle with approximately half of each group being withdrawn because of CBPP or showing CBPP lesions at post mortem examination. Clinical scores of the two groups were also similar. However cattle kept in contact with the danofloxacin-treated CBPP-affected animals showed significantly fewer lesions, less mortality and fewer animals were seropositive (P<0.02) and had reduced clinical scores (P<0.001) compared to cattle kept in contact with untreated CBPP-affected cattle. MmmSC was also isolated from fewer contact controls kept with the treated group. These findings could have important implications for the control of CBPP in Africa.     

Extended surveillance for CBPP in a free country: Challenges and solutions regarding the potential caprine reservoir

Contagious bovine pleuropneumonia (CBPP) is a severe respiratory disease of cattle and buffalo caused by Mycoplasma mycoides subsp. mycoides "Small Colony" (MmmSC). The agent of CBPP has been isolated from goats in different countries including CBPP-free areas. Goats can therefore be regarded as a putative MmmSC reservoir. No diagnostic test for CBPP surveillance in goats has been proposed as yet. Furthermore, serological tests could be seriously hampered by a widespread caprine infection due to the subspecies M. mycoides subsp. capri (Mmc), which is antigenically very close to MmmSC and displays high levels of genetic variability. A competition ELISA (cELISA) is currently used to screen for CBPP in cattle at the herd level in infected areas. The aim of this study was to see if the same cELISA would be specific enough to be used to screen goats despite the potential concomitant infection with Mmc. The cELISA titers of goats from Mmc-infected and non-infected herds were comparable and negative using the accepted cutoff for bovine sera. In contrast, seroconversion was observed in goats experimentally inoculated with an Mmc strain that cross-reacted with a monoclonal antibody targeting the same epitope as that used in cELISA. The probability of such false positivity occurring under field conditions is very low since Mmc strains with such an atypical antigenic profile emerge only rarely as a result of random nucleotide variation of the epitope-coding region. In conclusion, the commercially available cELISA can be considered specific enough to be used as a primary test to monitor passage of the CBPP agent in goats, but its sensitivity in goats requires further investigation.     

Indirect infection of cattle with contagious bovine pleuropneumonia.

Hay infected with Mycoplasma mycoides sub-species mycoides (M mycoides) was fed to six animals on three occasions. Five animals developed complement-fixing antibody in their sera and gave a positive reaction to the comparative intradermal allergic test. No animal died from contagious bovine pleuropneumonia (CBPP) but when they were killed, three had unequivocal lesions of the disease. M mycoides was isolated from the animals with these lesions but not from the others. CBPP was transmitted to two animals put in contact with those animals showing disease, and M mycoides was recovered from lesions in both animals. It is suggested that when unexplained outbreaks of CBPP occur, the possibility of indirect transmission should be considered.     

A minor role of CD4+ T lymphocytes in the control of a primary infection of cattle with Mycoplasma mycoides subsp. mycoides

ABSTRACT: Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides, is an important livestock disease in Africa. The current control measures rely on a vaccine with limited efficacy and occasional severe side effects. Knowledge of the protective arms of immunity involved in this disease will be beneficial for the development of an improved vaccine. In previous studies on cattle infected with M. mycoides subsp. mycoides, a correlation was detected between the levels of mycoplasma-specific IFN-γ-secreting CD4+ T lymphocytes and reduced clinical signs. However, no cause and effect has been established, and the role of such cells and of protective responses acquired during a primary infection is not known.We investigated the role of CD4+ T lymphocytes in CBPP by comparing disease patterns and post mortem findings between CD4+ T cell depleted and non-depleted cattle. The depletion was carried out using several injections of BoCD4 specific murine monoclonal antibody on day 6 after experimental endotracheal infection with the strain Afadé. All cattle were monitored clinically daily and sacrificed 28-30 days post-infection. Statistically significant but small differences were observed in the mortality rate between the depleted and non-depleted animals. However, no differences in clinical parameters (fever, signs of respiratory distress) and pathological lesions were observed, despite elimination of CD4+ T cells for more than a week. The slightly higher mortality in the depleted group suggests a minor role of CD4+ T cells in control of CBPP.     

Contagious bovine pleuropneumonia--a nearly forgotten disease?

Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subsp. mycoides small colony type (MmmSC) is a notifiable disease and has to be reported to the World Organisation for Animal Health (Office International des Epizooties, OIE, http://www.oie.int). Despite the fact that the last reported cases in Germany date back to 1926, the risk of introduction through clinically inconspicuous animals from countries where the disease is still endemic is rising. This is due mainly to an increase in international trade of live cattle and the failure to contain CBPP in many parts of Africa and elsewhere. To detect and eliminate this highly contagious infectious disease of the bovine respiratory tract, it is necessary to recognize matching clinical symptoms as soon as possible, as well as to have efficient methods for its detection on hand. In the present paper, we describe clinical manifestations and review state-of-the-art research, as well as currently used detection methods.     

Serological survey to determine the occurrence of respiratory Mycoplasma infections in the Polish cattle population

Mycoplasma bovis and Mycoplasma mycoides subspecies mycoides small colony (MmmSC) are causes of bovine mycoplasmosis and contagious bovine pleuropneumonia (CBPP), respectively, and are responsible for serious economic losses in cattle around the world. CBPP was last reported in Poland in 1939 but bovine mycoplasmosis is believed to be endemic. A survey of 3670 serum samples for antibodies to M bovis and MmmSC from 361 herds in 16 Polish provinces Poland between 2007 and 2010 found no evidence of CBPP. The seroprevalence of M bovis, however, appeared high with 76.7 per cent of samples giving a positive reaction in the ELISA test, which did not appear to reflect the clinical disease status of the cattle. Adjusting the sensitivity of the test reduced the prevalence to 28.2 per cent and reflects the levels reported in other European countries.     

Investigations into the role of carrier animals in the spread of contagious bovine pleuropneumonia.

An attempt was made to transmit contagious bovine pleuropneumonia (CBPP) from 22 animals recovered from artificial infection to healthy animals. Despite close contact and the imposition of a number of stresses no disease was transmitted. An unsuccessful attempt was made to reactivate old CBPP lesions by corticosteroid treatment, and by splenectomy. Four animals recovered from artificial infection did not become reinfected when put in contact with acute disease. Seven animals were reinoculated with Mycoplasmamycoides sub-species mycoides by endobronchial intubation. No clinical disease resulted. It is concluded that sequestra do not break down easily and that it is difficult to reinfect recovered animals. It is suggested that in field outbreaks of obscure origin, investigation should be thorough before it is concluded that an animal with an old sequestrum was responsible.     

Clinical, humoral and IFNgamma responses of cattle to infection with Mycoplasma mycoides var. mycoides small colony and attempts to condition the pathogenesis of the infection

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides var. mycoides small colony (MmmSC), is one of the most important diseases of cattle in Africa. The role of innate or acquired cell mediated and humoral immunity in conferring protection against MmmSC infection has not yet been elucidated. On the other hand, the pathological lesions caused by the aetiological agent have been considered indicative of an immunopathological process. In this study ten na?ve cattle were exposed to in-contact infection with animals infected by intubation with a strain of MmmSC. Clinical signs, antibody response, IFNgamma release and pathological changes at necropsy were analysed and compared with the events following in-contact infection of an equal number of animals kept under daily treatment with cyclosporine for the entire observation period of 84 days. Cyclosporine is a suppressor of the immune response related to the T-cell system. Under the conditions of the experiment, cyclosporine appeared to condition the pathogenesis of CBPP by delaying the events that follow infection, bringing further support to the possibility that the immune response may have an impact on the disease outcome.     

Serodiagnosis and monitoring of contagious bovine pleuropneumonia (CBPP) with an indirect ELISA based on the specific lipoprotein LppQ of Mycoplasma mycoides subsp. mycoides SC.

An indirect ELISA, based on the specific and strongly antigenic recombinant peptide of the N'-terminal half of the lipoprotein LppQ from Mycoplasma mycoides subsp. mycoides small colony type (SC) was developed for the detection of antibodies to M. mycoides subsp. mycoides SC. It was evaluated for its suitability for serodiagnosis and monitoring of contagious bovine pleuropneumonia (CBPP). The recombinant peptide containing poly-histidine residue tails was expressed in Escherichia coli and subsequently purified by Ni(2+) chelate affinity chromatography to be used as antigen to coat microtiter ELISA plates. The specificity of the antigen was tested against rabbit hyperimmune sera directed against related Mycoplasmas of the M. mycoides cluster and with sera from cattle that were either free of CBPP, but suffered from other mycoplasmal infections such as M. bovis, or showed cross-reactions in the complement fixation test. The sensitivity of the ELISA was assessed with sera from artificially infected animals and with sera from cattle originating from areas where CBPP was endemic at the time of blood sampling. The study revealed that the ELISA was both specific and sensitive for CBPP positive bovine sera and was shown also to be robust to harsh climatic conditions.     

Contagious bovine pleuropneumonia a review

Summary

The prevalence, characteristics of the aetiological agent, clinical signs, pathological changes, pathogenesis, epizootiology, microbiological and serological diagnosis, prevention, and control of contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subspecies mycoides SC type, are reviewed New aspects of the disease are discussed A renewed interest in this disease is important because of outbreaks in Southern Europe since 1980. When, at the end of 1992, the national borders of the countries of the European Community are abolished, it is conceivable that the disease will be introduced by cattle imported into CBPP‐free countries.     

Lung lesion score system in cattle: proposal for contagious bovine pleuropneumonia

Tropical Animal Health and Production - Contagious bovine pleuropneumonia (CBPP) is a severe infectious disease caused by Mycoplasma mycoides subsp. mycoides. The peculiar pathological features of...     

Analyses of baseline surveillance data on contagious bovine pleuropneumonia in the southern Sudan

In the first survey for contagious bovine pleuropneumonia (CBPP) in the southern region of the Sudan (Bahr el Ghazal Province), 8.1% of Dinka-owned, and 9.2% of Fellata-owned, cattle, and 48 and 20% of their respective herds were serologically positive for CBPP. Dinka cattle between 3 months and 3 years of age had significantly higher test reaction rates than those younger or older. There was a positive association between reaction rates and herd size. A similar association was found between crude mortality rates and herd size, though virtually none of the variability among herds in crude mortality was accounted for by presence of CBPP infection. Overall, the study indicated a highly endemic situation for CBPP infection with rare overt disease under conditions of little prior intervention. Under such conditions, it is suggested that a “surveillance and selective actions” rather than a “mass actions” approach might be the most suitable, with vaccination limited by surveillance to those areas at highest risk of outbreaks of clinically important CBPP, namely areas of low herd immunity or those where actual outbreaks of clinical disease have already occurred. Such an approach to CBPP could serve as a “model” for establishing a system of improved disease intelligence overall in the southern Sudan.     

Confirmation of the presence of Mycoplasma bovis in Hungarian cattle with pneumonia resembling pleuropneumonia.

Cattle from several farms in Hungary were investigated for the presence of mycoplasmal infections after the discovery of pulmonary lesions in some animals at slaughter. The pneumonic lesions, which resembled those of contagious bovine pleuropneumonia (CBPP) macroscopically and histologically were found to be caused by Mycoplasma bovis and not Mycoplasma mycoides subspecies mycoides (MmmSC) which is the causative agent of CBPP. No other bacterial pathogens were isolated. Negative results in complement fixation tests also showed that there was no serological evidence of CBPP. PCR tests for the detection of the M mycoides cluster and specifically for MmmSC were also negative. However, PCR and bacteriological culture detected cases of M bovis and the pneumonias may therefore be attributed to this mycoplasma.     

Within-herd spread of contagious bovine pleuropneumonia in Ethiopian highlands

Contagious bovine pleuropneumonia (CBPP) is a major threat for cattle health and production in Africa. This disease is caused by the small-colony type of Mycoplasma mycoides subspecies mycoides (MmmSC). Transmission occurs from direct and repeated contacts between sick and healthy animals. Veterinary services recently reported a resurgence of CBPP in the province of West Wellega, in the Ethiopian highlands. A research program was set up to estimate the epidemiological parameters of the within-herd infection spread. A follow-up survey was implemented in 71 sampled herds of the Boji district (West Wellega province). Fifteen herds were classified as newly infected and used in a serological- and clinical-incidence study. The overall 16-month cumulative sero-incidence risk was 34%. Clinical cases were recorded for 39% of the seropositive cattle; case-fatality risk was 13%. There was no evidence of benefit on infection spread of CBPP-control measures used locally by farmers (isolation or antibiotic treatments of sick animals). This might be related to a lack of power in the statistical analyses or to a quality problem for the medications used (and more generally, for health-care delivery in the Boji district).     

Contagious bovine pleuropneumonia. A review.

The prevalence, characteristics of the aetiological agent, clinical signs, pathological changes, pathogenesis, epizootiology, microbiological and serological diagnosis, prevention, and control of contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subspecies mycoides SC.type, are reviewed. New aspects of the disease are discussed. A renewed interest in this disease is important because of outbreaks in Southern Europe since 1980. When, at the end of 1992, the national borders of the countries of the European Community are abolished, it is conceivable that the disease will be introduced by cattle imported into CBPP-free countries.     

Salmonella Dublin infection in dairy cattle: risk factors for becoming a carrier

Long-term Salmonella Dublin carrier animals harbor the pathogen in lymph nodes and internal organs and can periodically shed bacteria through feces or milk, and contribute to transmission of the pathogen within infected herds. Thus, it is of great interest to reduce the number of new carrier animals in cattle herds. An observational field study was performed to evaluate factors affecting the risk that dairy cattle become carrier animals after infection with Salmonella Dublin. Based on repeated sampling, cattle in 12 Danish dairy herds were categorized according to course of infection, as either carriers (n = 157) or transiently infected (n = 87). The infection date for each animal was estimated from fecal excretion and antibody responses. The relationship between the course of infection (carrier versus transiently infected) and risk factors were analyzed using a random effect multilevel, multivariable logistic regression model. The animals with the highest risk of becoming carriers were heifers infected between the age of 1 year and 1st calving, and cows infected around the time of calving. The risk was higher in the first two quarters of the year (late Winter to Spring), and when the prevalence of potential shedders in the herd was low. The risk also varied between herds. The herds with the highest risk of carrier development were herds with clinical disease outbreaks during the study period. These findings are useful for future control strategies against Salmonella Dublin, because they show the importance of optimized calving management and management of heifers, and because they show that even when the herd prevalence is low, carriers are still being produced. The results raise new questions about the development of the carrier state in cattle after infection with low doses of Salmonella Dublin.     

Characterisation of the lymph node immune response following Mycoplasma mycoides subsp. Mycoides SC infection in cattle

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides biotype Small Colony (MmmSC), is still a major cattle disease in Africa. Development of long-term protective vaccines, the only relevant strategy to achieve CBPP eradication, requires the characterisation of the protective immune mechanism. To this aim, the present study investigated the cellular immune response persisting in the lymph nodes of cattle infected naturally and experimentally by contact, one year post exposure. The lymph node cell composition, MmmSC responsiveness and phenotype of the MmmSC-responding lymphocytes were compared between animals according to the different outcomes of the infection. To unravel the protective mechanism, the study focussed on the MmmSC-specific memory immune response generated in recovered cattle, known to develop long-term immunity and to be resistant to reinfection. An MmmSC-specific immune response, mediated by IFNgamma-secreting CD4 T-cells, was detected in the lymph nodes of all recovered cattle. Furthermore, the magnitude of this immune response was significantly higher in animals with complete recovery than in recovered animals presenting lung sequestra. The findings suggest that, in recovered cattle, a subset of MmmSC-primed IFNgamma-secreting CD4 T-cells homed to the regional lymph nodes as MmmSC-specific memory T-cells, likely responsible for the protective anamnestic response. Induction and expansion of this subset of MmmSC-specific CD4 memory T-cells might be a major goal to develop efficient long term protective vaccines against CBPP.     

Gamma interferon-producing CD4 T-cells correlate with resistance to Mycoplasma mycoides subsp. mycoides S.C. infection in cattle

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most significant cattle disease in Africa. The control measures, which led to eradication from numerous countries are not feasible in Africa where the only prophylaxis relies on vaccination. However, the attenuated vaccines, used up to now in Africa, are of low efficiency. The development of an improved vaccine is, therefore, a necessity. The purpose of this study was to compare some immunological parameters in MmmSC-infected cattle (endobronchial versus natural in-contact infection) and assess the response in correlation with the clinical outcome (death versus recovery). Characterization of the immune parameters elicited in recovered animals, known to be refractory to new infection, will be an important step towards development of new vaccines against CBPP. A significant outcome of this study was the demonstration that all MmmSC-infected cattle developed a MmmSC-specific cell-mediated immune response. A kinetic analysis of the MmmSC responsiveness showed that the main difference between endobronchially- and in-contact infected animals was the delay before the onset of the MmmSC-specific immune response. The first MmmSC-responding PBMC sample was selected from each animal for cell phenotyping. The phenotypic analysis of this early MmmSC-induced response revealed the predominant contribution of the CD4 T-cells in all animals whereas IFNgamma was only constantly produced in recovered animals. Evolution of this early MmmSC-specific immune response was then followed by a kinetic analysis of the MmmSC-induced CD4 T-cell response and IFNgamma released. The results demonstrated that in recovered animals, the MmmSC-specific CD4 Th1-like T-cell response was maintained until slaughtering whereas in animals with acute disease, progression of CBPP was associated with a decreased ability of the PBMC to produce IFNgamma. The results led to the identification of immune parameters, which correlate with protection against CBPP and to a relevant strategy for the development of improved vaccines against this disease.     

Comparison of complement fixation test,competitive ELISA and LppQ ELISA with post-mortem findings in the diagnosis of contagious bovine pleuropneumonia (CBPP)

The complement fixation test (CFT), the c-ELISA and an indirect LppQ ELISA were compared to post-mortem (PM) inspection for the diagnosis of contagious bovine pleuropneumonia (CBPP). Sera from 797 cattle in the CBPP affected area of Kazungula, Zambia and 202 sera from Lusaka, Zambia, a CBPP-free area were used. The clinical history of CBPP was recorded and all the cattle from Kazungula were slaughtered and PM inspections conducted. The prevalence of CBPP in Kazungula was 67.5% (95%CI 67.2%, 70.8%), 52.6% (95%CI 49.2%, 56.2%), 59.0% (95%CI 55.5%, 62.4%) and 44.4% (95%CI 41.0%, 47.9%) using PM inspection, CFT, c-ELISA and LppQ ELISA, respectively. Three of the 202 negative control animals tested positive on the c-ELISA although they were from a known CBPP negative zone. In this study, the c-ELISA was more sensitive in detecting cattle with lesions in the chronic stage than any other test whilst the CFT detected more during the onset stage. No single serological test could detect all stages of CBPP infection, therefore the use of more than one test is advised.     

Analysis of cellular responses to Mycoplasma mycoides subsp. mycoides small colony biotype associated with control of contagious bovine pleuropneumonia

A better understanding of protective immune memory against contagious bovine pleuropneumonia (CBPP) is needed in order to facilitate the development of safer vaccines based on selected components of the pathogen. For this purpose, cells collected from lymph nodes draining the lungs of Mycoplasma mycoides subsp. mycoides small colony biotype (MmmSC)-infected cattle were stimulated with the pathogen in vitro and evaluated concurrently for proliferation (CFSE based method), expression of activation, memory markers and cytokine production. Direct evidence is presented for a major contribution of CD4+ T cells to the vigorous proliferative and T1 biased cytokine recall responses observed in cattle that have recovered from infection but not in animals developing the acute form of the disease. Two different phenotypes of MmmSC-specific memory CD4 were observed based on CD62L expression and proliferative capacities. Furthermore, recall proliferation of B cells also occurred but was strictly dependent on the presence of CD4. The information provided in this study will facilitate the search for MmmSC antigens that have potential for the development of subunit vaccines against CBPP.