Parasitic zoonoses]

A review is given on Cryptosporidiosis, Giardiosis, Toxoplasmosis, Toxocarosis, Trichinellosis and Taeniosis.     

Small game (foxes, brown hares, pheasants and ducks) as carriers of zoonoses

Small game involves numerous infection hazards in terms of contact zoonoses and foodborne diseases. Especially exposed are hunters, game dealers, veterinarians, housewives, farmers, forest workers, laboratory staff, and taxidermists, but also consumers of insufficiently cooked game. This paper gives a survey of the most significant zoonoses in small game in Europe, which are discussed in the light of the author's own research results in this field. Finally, measures concerning prophylaxis and food hygiene are suggested.     

Economic aspects of zoonoses]

A significant economic evidence of zoonotic disease can be observed with costs of illness in the range of billions of DM. The lack of competitive structures in the German health care system calls for the use of economic evaluations. By the cautions use of these measures possibilities for rationalizing can be discovered and utilized.     

Cryptosporidium and Giardia as foodborne zoonoses

Cryptosporidium and Giardia are major causes of diarrhoeal disease in humans, worldwide and are major causes of protozoan waterborne diseases. Both Cryptosporidium and Giardia have life cycles which are suited to waterborne and foodborne transmission. There are 16 'valid'Cryptosporidium species and a further 33+ genotypes described. Parasites which infect humans belong to the Giardia duodenalis "type", and at least seven G. duodenalis assemblages are recognised. Cryptosporidium parvum is the major zoonotic Cryptosporidium species, while G. duodenalis assemblages A and B have been found in humans and most mammalian orders. In depth studies to determine the role of non-human hosts in the transmission of Cryptosporidium and Giardia to humans are required. The use of harmonised methodology and standardised and validated molecular markers, together with sampling strategies that provide sufficient information about all contributors to the environmental (oo)cyst pool that cause contamination of food and water, are recommended. Standardised methods for detecting (oo)cysts in water are available, as are optimised, validated methods for detecting Cryptosporidium in soft fruit and salad vegetables. These provide valuable data on (oo)cyst occurrence, and can be used for species and subspecies typing using appropriate molecular tools. Given the zoonotic potential of these organisms, epidemiological, source and disease tracking investigations involve multidisciplinary teams. Here, the role of the veterinarian is paramount, particularly in understanding the requirement for adopting comprehensive sampling strategies for analysing both sporadic and outbreak samples from all potential non-human contributors. Comprehensive sampling strategies increase our understanding of parasite population biology and structure and this knowledge can be used to determine what level of discrimination is required between isolates. Genetic exchange is frequent in C. parvum populations, leading to recombination between alleles at different loci, the generation of a very large number of different genotypes and a high level of resolution between isolates. In contrast, genetic exchange appears rare in Cryptosporidium hominis and populations are essentially clonal with far fewer combinations of alleles at different loci, resulting in a much lower resolution between isolates with many being of the same genotype. Clearly, more markers provide more resolution and high throughput sequencing of a variety of genes, as in multilocus sequence typing, is a way forward. Sub-genotyping tools offer increased discrimination, specificity and sensitivity, which can be exploited for investigating the epidemiology of disease, the role of asymptomatic carriers and contaminated fomites and for source and disease tracking for food and water contaminated with small numbers of (oo)cysts.     

Vibrios as causal agents of zoonoses

Vibrios are Gram-negative rod-shaped bacteria that are widespread in the coastal and estuarine environments. Some species, e.g. Vibrio anguillarum and V. tapetis, comprise serious pathogens of aquatic vertebrates or invertebrates. Other groups, including Grimontia (=Vibrio) hollisae, Photobacterium (=Vibrio) damselae subsp. damselae, V. alginolyticus, V. harveyi (=V. carchariae), V. cholerae, V. fluvialis, V. furnissii, V. metschnikovii, V. mimicus, V. parahaemolyticus and V. vulnificus, may cause disease in both aquatic animals and humans. The human outbreaks, although low in number, typically involve wound infections and gastro-intestinal disease often with watery diarrhoea. In a minority of cases, for example V. vulnificus, there is good evidence to actually associate human infections with diseased animals. In other cases, the link is certainly feasible but hard evidence is mostly lacking.     

Arthropoda as zoonoses and their implications.

Some aspects of changing patterns of arthropodal infections and arthropod-borne diseases in Mediterranean areas are briefly discussed. Selected examples are given, with particular emphasis on the phenomenon of the synanthropic flea Ctenocephalides felis felis and on health problems caused by human infections with Argas reflexus, the common tick of urban pigeons in Europe. Finally, the risk of the emergence of Lyme borreliosis (Borrelia burgdorferi) is considered in relation to the increasing spread of environmental infestation with ticks, mainly Ixodes ricinus, an efficacious vector for the spirochaete.     

Microbiological studies of wild rodents in farms as carriers of pig infectious agents

In 15 breeding and fattening pig herds, 85 mice (Mus musculus) and 40 rats (Rattus norvegicus) were captured and bacteria and viruses looked for. Bordetella bronchiseptica, Pasteurella sp., E. coli, Campylobacter jejuni and Treponema sp. were isolated from different samples. Rota-virus was also identified and neutralizing transmissible gastroenteritis antibodies were detected in the serum of one rat and mice from three different farms. Wild rats were also orally infected with Aujeszky's disease virus (ADV) and classical swine fever (CSF) virus. All the rats survived the ADV experimental infection and some of them showed ADV neutralizing antibodies in their sera. No multiplication of the SF virus was obtained.     

Emergence of "new" viral zoonoses]

In the last two to three decades a significant increase of viral zoonotic infections was observed. These zoonoses are not only newly (or previously unrecognized) emerging diseases, but also due to the reappearance of diseases thought to have been defeated (re-emerging diseases). "New" viral diseases can arise when viruses broaden their host-range (monkey poxvirus; equine morbillivirus), or can be a consequence of intrinsic properties of the virus itself, such as high mutation rates (influenza A virus). Most new or reemerging viral zoonoses are due to infections with hemorrhagic viruses. Many of them are transmitted by insects (arboviruses, e.g. yellow fever virus) or by rodents (e.g. Hanta viruses), others by contact with patients and nosocomial infections (e.g. Ebola virus). The emergence and increase of these diseases are a consequence of anthropogenic environmental changes, such as distortions of the ecological balance and changes in agriculture. In addition, the uncontrolled growth of the cities in tropical and subtropical regions without improvement of the public health measures and the increasing international animal trade and travel also favour the spread and recurrence of these diseases.     

Immunity to Swine dysentery in recovered pigs

The immune status of 29 pigs recovered from swine dysentery (SD) was evaluated after reexposure to Treponema hyodysenteriae. Pigs which had recovered from SD and remained asymptomatic for 4 to 6, 9 to 13, and 16 to 17 weeks after initial inoculation were reexposed to 1.5 X 10(9) viable cells of T hyodysenteriae per pig. Pigs which had recovered from SD were not shedding T hyodysenteriae, as determined by selective cultural examination of feces, before they were reexposed. Of 29 pigs reexposed to T hyodysenteriae, 27 were resistant to SD. In contrast, 23 of 28 control pigs developed signs of SD when exposed to T hyodysenteriae for the first time. Significant differences in immunity were not observed between pigs from the three convalescent periods. Serum agglutinins to T hyodysenteriae were present in recovered pigs for approximately 8 weeks after inoculation.     

广东部分地区中小型猪场猪伪狂犬病野毒感染的血清学调查

采用阻断ELISA法,对广东省9个地区经猪伪狂犬基因缺失苗免疫的中小型猪场2005年-2006上半年送检的375份血清进行猪伪狂犬病野毒感染的血清学检测。结果表明,有9个地区猪场血清呈阳性,其中阳性血清174份,平均阳性率为46.4%,最高阳性率达65.0%,提示该地区中小型猪场有猪伪狂犬病野毒感染。     

特种野猪饲养管理新技术

特种野猪是以纯种野猪做父本,优良家猪做母本杂交培育的一代新猪种。它保持了野猪瘦肉率高、适应性强、野味浓厚和家猪繁殖性能好。肉质脆嫩的优点。野猪肉营养丰富,含有17种氨基酸,人体只能通过食品摄取而自身不能合成的必需脂肪酸——亚油酸含量比家猪高2.5倍,另外,还含有大量抗癌物质锦和硒等,故其养殖前景日渐看     

华南地区猪群猪流感病毒病原学和血清学调查

为了解华南地区猪群中猪流感病毒(SIV)的流行及其遗传变异情况,本研究从2016年~2017年广东、广西等地猪群236份猪肺脏病料组织和143份鼻拭子样品中分离鉴定得到3株SIV,全基因组测序和遗传演化分析结果显示,3个分离株均属于H1N1亚型欧亚类禽分支SIV,并且均与pdm09分支病毒株发生了重组。HA蛋白分子特征分析结果显示,A/Swine/Guangxi/NK/2016 HA蛋白第23位糖基化位点发生了缺失。3265份血清样品抗体监测结果显示,欧亚类禽H1N1、pdm09 H1N1和H3N2 SIV的血清抗体阳性率分别为27.53%、20.98%和34.85%。另外,0.64%的(21份)血清样品为H9N2亚型流感病毒抗体阳性,并且猪群中不同亚型和不同分支SIV之间混合感染的情况非常普遍。猪群中流感病毒血清抗体监测结果显示,EA H1N1、pdm09和H3N2亚型SIV HI抗体滴度最高均可达到1:1280,而H9N2亚型HI抗体滴度最高为1:160,表明H9N2 AIV虽然可以感染猪,但对猪还不适应。各月份的血清抗体阳性率分析显示,SIV的流行具有季节性,冬季(11月、12月和1月份)的流行最为严重。本研究可为华南地区猪群SI防控及疫苗株的筛选提供参考依据。