A survey of brucellosis and tuberculosis in bison in and around Wood Buffalo National Park, Canada

Examinations of complete or partial remains of 72 bison found dead in and around Wood Buffalo National Park, Canada, revealed evidence of brucellosis in 18 (25%) and tuberculosis in 15 (21%), with a combined prevalence of 42%. Urease-positive and ureasenegative strains of Brucella abortus biovar 1, and strains of biovar 2, were isolated from tissues of bison, including synovium and exudate from severe arthritic lesions. Mycobacterium bovis was isolated from a range of granulomatous lesions that were similar to those reported in tuberculous cattle. Diseased bison had a broad geographical distribution, and were found outside the park on at least three natural corridors. The diseases have a deleterious effect on this population of bison, and pose a health risk to other bison herds, livestock, and native hunters in the region.     

Infection of cattle with Brucella abortus biovar 1 isolated from a bison in Wood Buffalo National Park.

An experiment was conducted to determine if cattle could be infected with a strain of Brucella abortus biovar 1 isolated from a bison in Wood Buffalo National Park. Three pregnant cows inoculated conjunctivally with 5.7 x 10(8) cfu of the bacterium, and their subsequent calves, showed seroconversion on standard serological tests for bovine brucellosis, and large numbers of the bacterium were isolated from numerous tissues at necropsy. A 4th cow that was moved into the pen that previously contained the inoculated cows subsequently showed seroconversion, and the same strain of B. abortus biovar 1 was isolated from numerous tissues. Although this strain from bison in Wood Buffalo National Park has existed in isolation from cattle for over 60 years, it remains infectious and contagious for cattle.     

Ecology and epidemiology of anthrax in cattle and humans in Zambia

Anthrax is endemic in Western and North-western Provinces of Zambia. The disease occurs throughout the year and impacts negatively on the economy of the livestock industry and public health in Zambia. During 1989-1995, there were 1626 suspected cases of anthrax in cattle in Western province and of these 51 were confirmed. There were 220 cases of human anthrax cases in 1990 alone and 248 cases during 1991-1998 with 19.1% and 7.7% case fatality rates, respectively. Interplay of the ecology of affected areas and anthropogenic factors seem to trigger anthrax epidemics. Anthrax has drawn considerable attention in recent years due to its potential use as a biological weapon. In this paper, the history, current status and approaches towards the control of the disease in Zambia are discussed. Quarantine measures restrict trade of livestock and exchange of animals for draught power resulting in poor food security at household levels. Challenges of anthrax control are complex and comprise of socio-political, economical, environmental and cultural factors. Inadequate funding, lack of innovative disease control strategies and lack of cooperation from stakeholders are the major constraints to the control of the disease. It is hoped that the information provided here will stimulate continued awareness for the veterinary and medical authorities to maintain their surveillance and capabilities against the disease. This may lead to a culminating positive impact on livestock and human health in the southern African region.     

Aspects of the epidemiology of bovine staphylococcal mastitis

Abstract

Strains of Staphylococcus aureus which are not susceptible to many antibiotics are now generally regarded as the most important pathogens in bovine mastitis. More effective methods for controlling the disease must, therefore, take into account recent advances in our knowledge of the epidemiology of the disease. These include information about the principal habitats of S. aureus in the host, the minimal numbers of organisms that may establish new udder infections, which animals act as reservoirs of infection in herds, and the transmission of infection in lactating and non-lactating cows. Such matters are discussed in relation to the application of mastitis control measures involving herd management, hygiene, antibiotic therapy, culling and milking machine maintenance.     

Feeding habits and flight range of blow-flies (Chrysomyia spp.) in relation to anthrax transmission in the Kruger National Park, South Africa

Carrion-frequenting blow-flies (Chrysomyia albiceps and C. marginalis) were allowed 4 days of feeding on 32P-orthophosphate-labelled blood or an impala carcass (Aepyceros melampus) in the northern Kruger National Park, South Africa. The dispersal and density of fly faecal and discard droplets were then established using a Geiger-Counter, indicating that most droplets occurred between a height of 1 and 3 m on nearby leaves and twigs. This coincides with the preferred feeding height of kudu (Tragelaphus strepsiceros). During a previous anthrax epizootic kudu comprised 73.15% of a total medium to large mammal mortality figure of 1054. Further analysis of mortality shows browsers to have been most severely affected, and it is suggested that this is correlated with feeding habits of these animals. Trapping also yielded radioactively labelled C. albiceps up to 32.5 km and C. marginalis up to 25 km from the isotope source.     

The epidemiology of tuberculosis in free-ranging African buffalo (Syncerus caffer) in the Kruger National Park, South Africa

The presence of bovine tuberculosis (Mycobacterium bovis) in the Kruger National Park (KNP) was determined for the first time in 1990. It was diagnosed in an African buffalo (Syncerus caffer) bull, which was found recumbent and in an emaciated and moribund state near the south-western boundary fence. This prompted an investigation into the bovine tuberculosis (BTB) status of the KNP, with emphasis on its epidemiological determinants and risk factors. This report documents the findings of surveys that were conducted from 1990 to 1996. It was found that BTB had entered the KNP ecosystem relatively recently (+/- 1960), and has found favourable circumstances for survival and propagation in a fully susceptible and immunologically naive buffalo population. Indications are that it entered the KNP from across the southern river boundary, where the presence of infected domestic cattle herds had been documented. From there the infection spread through the southern buffalo population and is currently spreading in a northward direction. It was estimated that this northward spread took place at a rate of about 6 km per year; the prospect being that, if this rate of spread is maintained, the entire KNP may be affected in less than 30 years from now. Spillover from buffalo had already occurred in species such as chacma baboon (Papio ursinus), lion (Panthera leo), cheetah (Acinonyx jubatus), kudu (Tragelaphus strepsiceros) and leopard (Panthera pardus). Although there is no indication yet that these species act as maintenance hosts, the possibility is raised that these, or an as yet overlooked species, might assume such a role in future. In the KNP, BTB manifests itself as a chronic and predominantly subclinical disease in buffalo. It may take years for clinical signs to develop, and then only at a terminal stage, when emaciation is a constant feature. It is suspected that the time from infection to death is variable and dependent on the animal's immune response, which can be weakened by such factors as stress, old age or droughts. It was found that, in the interim, buffalo have a normal reproductive life. On necropsy, buffalo show almost exclusively lung and upper respiratory tract involvement, pointing to an aerogenous mode of transmission. Histologically, little sign of encapsulation of lesions was detected, which suggests that they are exceptionally susceptible to BTB and that most lesions are open and infectious and progressive, leading ultimately to death of the individual. Evidence also indicates that BTB is progressive within the herd context (92% being the highest prevalence rate thus far determined in a buffalo herd) as well as progressive within the KNP buffalo population (the implication being that virtually all buffalo herds in the KNP will eventually be infected). Preliminary data suggest a positive correlation between disease prevalence and mortality, with potential mortality reaching up to 10% in buffalo herds having BTB prevalence rates of 50 % and higher. Only the future will tell what the effect of the disease on the population dynamics of buffalo will be.     

Aspects of the diagnosis, pathogenesis and epidemiology of canine parvovirus

Between 18 July 1980 and 2 January 1981, 188 samples (145 faeces and 43 intestinal contents) were submitted from dogs with suspected canine parvovirus (CPV) enteritis. CPV was demonstrated in 56 (30%) of these samples; the weekly rate of positive CPV identification was remarkably constant at approximately 30% even though clinical and often post-mortem findings strongly supported a diagnosis of CPV enteritis. The simplest, most sensitive and most rapid method for detection of virus was haemagglutination (HA) which was twice as sensitive as isolation of virus and 8 times as sensitive as electron microscopy (EM). Forty nine of 56 (88%) samples positive for CPV were from dogs less than 1 year old and 44 (79%) CPV-positive samples were from pups less than 6 months old; only one sample from a pup less than 2 months old (pup was 7 weeks old) was positive. An additional 68 samples (53 faeces and 15 intestinal contents) were submitted from Beagle dogs that were part of a colony of approximately 1200 dogs. Epidemiological data pinpoints the entry of CPV into the colony in November 1978 at which time most dogs including pups less than 6 months of age developed antibody to CPV without developing clinical disease. From these data an overview of some aspects of the pathogenesis and epidemiology of CPV is constructed.     

Fire behaviour in the Kruger National Park

Abstract

Fire research in the Kruger National Park has largely been focussed on the effect of the season and frequency of burning on the vegetation. Very little information is available on the effect of fire behaviour and in particular fire intensity, on the flora of the Park. Consequently a research project was conducted to develop statistical models for predicting fire intensity, flame height and rate of spread in the field. The devleopment of these models constitutes the initial phase of determining the relationship between fire behaviour and vegetation response.     

The effect of seasonal variation on anthrax epidemiology in the upper Zambezi floodplain of western Zambia

Anthrax has become endemic throughout the upper Zambezi floodplain located in the Western Province of Zambia over the recent years. To date, no comprehensive study has been carried out to determine whether recurrence of anthrax outbreaks may be linked to differences in precipitation and human activities. Retrospective data for the period 1999 to 2007 showed that a total of 1,216 bovine cases of anthrax were reported. During the same period, 1,790 human anthrax cases and a corresponding case fatality rate of 4.63% (83/1,790) was documented in the upper Zambezi floodplain. Occurrence of human cases was highly correlated with cattle outbreaks (r = 0.94, p < 0.001). Differences in precipitation were significantly associated with the occurrence of anthrax outbreaks (χ² = 4.75, p < 0.03), indicating that the likelihood of outbreaks occurring was higher during the dry months when human occupancy of the floodplain was greater compared to the flooding months when people and livestock moved out of this region. Human dependency on the floodplain was shown to significantly influence the epidemiology of anthrax in the upper Zambezi floodplain of western Zambia. Methods for mitigating anthrax outbreaks by disrupting the cycle of transmission are herein highlighted.     

Aspects of the epidemiology of nematode infections in a cow-calf herd in Ontario.

On May 29, 1980, 108 cows and calves were placed on a 20 hectare pasture until October 26, except that from September 18 to October 2 they were in a barn. Every two weeks during the total period, fecal samples were taken from 17 cows and 14 calves and herbage samples were collected from the pasture. Parasite fecal egg counts were estimated using the Cornell-Wisconsin centrifugation technique and herbage infective larvae by a modified Sandwich technique. Daily maximum and minimum air temperature and precipitation were recorded. The principal parasite egg found was the trichostrongyle-strongyle morulate, oval-shaped egg referred to as a gastrointestinal nematode (GIN) egg. The mean GIN egg/g of feces for cows varied from 14.2 to 23.9 and for calves it rose from 0.2 in the spring to 134.8 in the fall. Nematodirus, Trichuris, Strongyloides, Moniezia and coccidia were also found. Larvae were recovered first in July, with the greatest number, over 2000/kg of dry weight of herbage, in September and were primarily Cooperia and Ostertagia.     

Isolation of Rhodococcus equi from the feces of indigenous animals and soil from the Lower Zambezi National Park and Lochinvar National Park, Zambia

Rhodococcus equi is an important pathogen in foals; however, its incidence in African indigenous animals is poorly understood. Fecal samples (92 from nine indigenous species) and 43 soil samples were collected from two Zambian National Parks. The presence of R. equi was investigated and 533 isolates were tested for the presence of 15- to 17-kDa antigens (VapA) and a 20-kDa antigen (VapB) by immunoblotting and PCR. R. equi was isolated (10(2)-10(4) colony forming units/g) from 75% of fecal and 74% of soil samples. Neither antigen was detected; however, about 20% of the isolates contained cryptic plasmids of various sizes. There was no evidence of virulent R. equi, but the avirulent form was widespread in the animals and the soil.     

Drag-sampling of free-living ixodid ticks in the Kruger National Park

Free-living ticks were collected by means of drag-sampling in 32 of the 35 landscape zones of the Kruger National Park during a period of 1 calendar month. Of the 18,199 specimens collected, 99.53% were larvae, 0.05% nymphs and 0.42% adults. Fourteen species were collected. Amblyomma hebraeum followed by Boophilus decoloratus, predominated, both in distribution and abundance. Large variations were encountered between drags. There was no correlation between the numbers of larvae collected and time of day, temperature, grass length, vegetation biomass estimates and subzone type.     

巴基斯坦红其拉甫国家公园野生脊椎动物区系与分布特征研究

红其拉甫国家公园（国家自然保护区）建立于1975年,地处巴基斯坦北部地区,喀喇昆仑山南坡,介于N36°45.5′和E74°49.7′之间,总面积约5 600 km^2。本研究通过实地考察和查阅相关文献资料,对分布于该地区的野生动物从区系组成、区系性质的角度进行了分析。结果表明,该地区共有野生脊椎动物24目54科113属160种,其中鱼类1目2科7属11种,两栖类1目1科1属2种,爬行类1目3科5属8种,鸟类14目34科72属103种,哺乳类/兽类7目14科28属36种。160种动物中,列入国际自然保护联盟（IUCN）和濒危动植物种国际贸易公约（CITES）红色名录和附录的濒危、易危和低危物种有24种。按照李思忠和高行宜等依据世界动物分布型对中国野生脊椎动物所划分的15个分布区（区系）类型,对所整理和统计的野生脊椎动物进行地理成分分析表明,该地区分布的野生脊椎动物可归入8个分布区系类型和3个复合体。其中,北方广布种、高地型种和古北型种最多,分别有39种、34种和23种,占该地区野生动物总种数的21.37%、21.25%和15.00%。由此表明,古北界和全北界属性是该地区动物区系的基本特征。与此同时,该地区动物区系与中亚型-全北型交错较多,其次为东洋型与喜马拉雅-横断山型有一定的交错,而鱼类与两栖类区系成分和复合体的交错分布甚少。     

冰与火的奇境冰岛瓦特纳冰川国家公园

在著名电影《星际穿越》中,神秘的星际航行、超现实的宇宙黑洞、细腻的亲情戏,让人震惊而感动.而影片里的那些奇幻场景,更是给人留下了深刻印象.尤其是冰冻星球曼恩星,那一望无际的冰川世界给人万径人踪灭的寂寥感,在视觉上令人极度震撼.不过,更令人震撼的是,那些场景并不是特效,而是现实社会中的真实存在——冰岛的瓦特纳冰川国家公园.