RESUMEN
UNLABELLED: During the routine fingerprinting of outbreak strains of Bacillus anthracis of European and African origin by means of a 31-marker multi-locus variable number of tandem repeats analysis (MLVA), four cultures, two from the Etosha National Park (ENP), Namibia, and two from an outbreak in the Pyrenees in 1997, were found to harbour different genotypes (GTs). To investigate this further, isolates from 10 samples of blood-soaked soil from beneath anthrax carcasses and 18 clinical swabs taken from carcasses in the ENP were examined by a 31-marker MLVA. While only a single GT was found in any one of the 10 soil samples, four of the 18 swabs (22%) yielded different GTs. Two GTs were isolated from each of a zebra and a springbok and three GTs from each of a second zebra and an elephant. These animals had died in a region of the ENP where deaths caused by anthrax regularly occur every year. The results confirm the indications noted previously that co-infection with more than one GT is probably not especially uncommon. The results show that, for the purpose of analysing genotypes involved in an outbreak, it is important to examine more than a single colony from a clinical sample. SIGNIFICANCE AND IMPACT OF THE STUDY: Multi-locus variable number of tandem repeats analysis (MLVA)-based fingerprinting techniques have been used in many studies worldwide to characterize the occurrence of different genotypes of Bacillus anthracis in outbreaks of wildlife or livestock and to draw conclusions about the source, the possible routes of spread and the temporal and spatial distribution of outbreak strains. Simultaneous isolation of different genotypes from the same host revealed in our study by MLVA highlights the importance of examining more than a single colony from a clinical sample. This conclusion is not specific for MLVA but holds true for every high-resolution method, including full-genome sequencing.
Asunto(s)
Animales Salvajes/microbiología , Carbunco/veterinaria , Bacillus anthracis/genética , Bacillus anthracis/aislamiento & purificación , Coinfección/veterinaria , Animales , Carbunco/epidemiología , Carbunco/microbiología , Bacillus anthracis/clasificación , Coinfección/microbiología , Brotes de Enfermedades , Elefantes , Equidae , Europa (Continente)/epidemiología , Genotipo , Repeticiones de Minisatélite , Namibia/epidemiología , Microbiología del SueloRESUMEN
The simple polychrome methylene blue (PMB) staining procedure for blood or tissue smears from dead animals (M'Fadyean reaction) established in 1903 remained accepted as a highly reliable, rapid diagnostic test for anthrax for six decades while that disease was still common in livestock throughout the world. Improvements in disease control led to anthrax becoming rare in industrialized countries and less frequent in developing countries with the result that quality controlled, commercially produced PMB became hard to obtain by the 1980s. Mixed results with alternative methylene blue-based stains then led to diagnosis failures, confusion among practitioners and mistrust of this procedure as a reliable test for anthrax. We now report that, for laboratories needing a reliable M'Fadyean stain at short notice, the best approach is to have available commercially pure azure B ready to constitute into a solution of 0.03 g azure B in 3 ml of 95% ethanol or methanol to which is then added 10 ml of 0.01% KOH (0.23% final azure B concentration) and which can then be used immediately and through to the end of the tests. Stored in the dark at room temperature, the shelf life is at least 12 months. Smears should be fixed with ethanol or methanol (95-100%), not by heat, and the stain left for 5 min before washing off for optimum effect.
Asunto(s)
Carbunco/diagnóstico , Bacillus anthracis/citología , Cápsulas Bacterianas/metabolismo , Técnicas Bacteriológicas/métodos , Colorantes/metabolismo , Coloración y Etiquetado/métodos , Carbunco/microbiologíaRESUMEN
Anthrax is the archetype zoonosis; no other infectious disease affects such a wide range of species, including humans, although most susceptible are herbivorous mammals. Although the disease appears to have been recognized for centuries, it has yet to be established scientifically how animals contract it. While primarily a disease of warmer regions, it has long been spread to cooler zones through the trade of infected animals or contaminated animal products. Today it is still endemic in many countries of Africa and Asia and non-endemic countries must remain alert to the possibility of imports from such endemic areas resulting in outbreaks in their own livestock. The epidemiology of anthrax is becoming understood better with new systems coming on stream for distinguishing different genotypes and this is covered in detail. Clinical signs and pathology in animals are described.
Asunto(s)
Enfermedades de los Animales , Carbunco , Zoonosis , África/epidemiología , Enfermedades de los Animales/epidemiología , Enfermedades de los Animales/patología , Enfermedades de los Animales/transmisión , Animales , Animales Domésticos/microbiología , Carbunco/epidemiología , Carbunco/patología , Carbunco/transmisión , Asia/epidemiología , Bacillus anthracis/genética , Bacillus anthracis/patogenicidad , Aves/microbiología , Carnívoros/microbiología , Enfermedades Transmisibles/epidemiología , Enfermedades Transmisibles/patología , Enfermedades Transmisibles/transmisión , Brotes de Enfermedades , Genotipo , Humanos , Esporas Bacterianas/metabolismo , Zoonosis/epidemiología , Zoonosis/transmisiónRESUMEN
Sera from 19 wild caught vultures in northern Namibia and 15 (12 wild caught and three captive bred but with minimal histories) in North West Province, South Africa, were examined by an enzyme-linked immunosorbent assay (ELISA) for antibodies to the Bacillus anthracis toxin protective antigen (PA). As assessed from the baseline established with a control group of ten captive reared vultures with well-documented histories, elevated titres were found in 12 of the 19 (63%) wild caught Namibian birds as compared with none of the 15 South African ones. There was a highly significant difference between the Namibian group as a whole and the other groups (P < 0.001) and no significant difference between the South African and control groups (P > 0.05). Numbers in the Namibian group were too small to determine any significances in species-, sex- or age-related differences within the raw data showing elevated titres in four out of six Cape Vultures, Gyps coprotheres, six out of ten White-backed Vultures, Gyps africanus, and one out of three Lappet-faced Vultures, Aegypius tracheliotus, or in five of six males versus three of seven females, and ten of 15 adults versus one of four juveniles. The results are in line with the available data on the incidence of anthrax in northern Namibia and South Africa and the likely contact of the vultures tested with anthrax carcasses. It is not known whether elevated titre indicates infection per se in vultures or absorption of incompletely digested epitopes of the toxin or both. The results are discussed in relation to distances travelled by vultures as determined by new tracking techniques, how serology can reveal anthrax activity in an area and the issue of the role of vultures in transmission of anthrax.
Asunto(s)
Carbunco/veterinaria , Anticuerpos Antibacterianos/sangre , Antígenos Bacterianos/inmunología , Bacillus anthracis/inmunología , Enfermedades de las Aves/epidemiología , Falconiformes , África Austral/epidemiología , Factores de Edad , Animales , Carbunco/epidemiología , Carbunco/transmisión , Enfermedades de las Aves/transmisión , Ensayo de Inmunoadsorción Enzimática/métodos , Ensayo de Inmunoadsorción Enzimática/veterinaria , Femenino , Cadena Alimentaria , Masculino , Estudios Seroepidemiológicos , Factores Sexuales , Especificidad de la EspecieRESUMEN
A massive outbreak of anthrax in the wildlife of the Malilangwe Wildlife Reserve in Zimbabwe between August and November 2004 resulted in the death of almost all the reserve's estimated 500 kudu (Tragelaphus strepsiceros). Other species badly affected were nyala (Tragelaphus angasi), bushbuck (Tragelaphus scriptus), waterbuck (Kobus ellipsiprymnus) and roan antelope (Hippotragus equinus), which suffered losses of approximately 68 per cent, 48 per cent, 44 per cent and 42 per cent of their populations, respectively. Buffalo (Syncerus caffer) were also badly affected and although their population suffered only a 6 per cent loss, the numbers of deaths ranked second highest after kudu. To the authors' knowledge, this is the first record of anthrax in wildlife in Zimbabwe.
Asunto(s)
Antílopes , Carbunco/veterinaria , Brotes de Enfermedades/veterinaria , Rumiantes , Animales , Animales Salvajes , Carbunco/epidemiología , Carbunco/prevención & control , Vacunas contra el Carbunco/administración & dosificación , Bacillus anthracis/inmunología , Femenino , Masculino , Estaciones del Año , Vacunación/veterinaria , Zimbabwe/epidemiologíaRESUMEN
Institution of a policy of vaccination in endangered species with a vaccine not previously administered to it cannot be undertaken lightly. This applies even more in the case of cheetah (Acinonyx jubatus) with their unusually monomorphic gene pool and the potential restrictions this places on their immune responses. However, the recently observed mortalities from anthrax in these animals in the Etosha National Park, Namibia, made it imperative to evaluate vaccination. Black rhinoceros (Diceros bicornis), another endangered species in the park, have been vaccinated for over three decades but the effectiveness of this has never been evaluated. Passive protection tests in A/J mice using sera from 12 cheetahs together with enzyme immunoassay indicated that cheetah are able to mount seemingly normal primary and secondary humoral immune responses to the Sterne 34F2 live spore livestock vaccine. Overall protection rates in mice injected with the sera rose and fell in concert with rises and declines in antibody titres, although fine analysis showed that the correlation between titre and protection was complex. Once a high level of protection (96% of mice 1 month after a second booster in the cheetahs) had been achieved, the duration of substantial protection appeared good (60% of the mice 5 months after the second booster). Protection conferred on mice by sera from three of four vaccinated rhino was almost complete, but, obscurely, none of the mice receiving serum from the fourth rhino were protected. Sera from three park lions with naturally acquired high antibody titres, included as controls, also conferred high levels of protection. For the purposes of wildlife management, the conclusions were that vaccination of cheetah with the standard animal anthrax vaccine causes no observable ill effect in the animals and does appear to confer protective immunity. At least one well-separated booster does appear to be desirable. Vaccination of rhino also appears to be justified from the limited data obtained.
Asunto(s)
Acinonyx/inmunología , Vacunas contra el Carbunco/uso terapéutico , Carbunco/prevención & control , Carbunco/veterinaria , Artiodáctilos/inmunología , Animales , Vacunas contra el Carbunco/efectos adversos , Anticuerpos Antibacterianos/análisis , Anticuerpos Antibacterianos/biosíntesis , Anticuerpos Antibacterianos/uso terapéutico , Ensayo de Inmunoadsorción Enzimática , Femenino , Inmunización Pasiva , Masculino , RatonesRESUMEN
The familiarity with the ancient disease anthrax from the second millennium B.C. through the second millennium A.D. is reviewed, providing the backdrop to the modern understanding of this disease as covered in the remainder of the volume. By means of an overview of the aetiology, ecology, epidemiology, clinical manifestations, pathology and bacteriology of the naturally acquired disease, this opening chapter also lays down the groundwork for the subsequent state-of-the-art chapters.