Lactococcus garvieae in fish: a review

Lactococcus garvieae is the etiological agent of Lactococcosis, an emergent disease which affects many fish species and causes important economic losses both in marine and freshwater aquaculture when water temperature increases over 16 degrees C in summer months. Normally, it causes a hyperacute and haemorrhagic septicemia. This paper presents a state of the art review of fish Lactococcosis including aspects such as pathogen characterization, pathogenesis, epidemiology, diagnosis and control measures of the disease in farmed fish.     

Ornithobacterium rhinotracheale infections in poultry: a review

O. rhinotracheale is a relatively new bacterium. It is found in commercial fowl and wild birds throughout the world. O. rhinotracheale causes respiratory disease, presenting as pneumonia and air sacculitis. It is transmitted horizontally as well as vertically. O. rhinotracheale is difficult to isolate. Serologically, twelve serotypes can be distinguished, of which serotype A is the most prevalent. Treatment can be difficult, because acquired resistance against the regular antibiotics is common in O. rhinotracheale isolates. An inactivated vaccine for broiler breeders has been developed and for turkeys an inactivated autovaccine can be made.     

Viral infections and bovine mastitis: a review

This review deals with the role of viruses in the aetiology of bovine mastitis. Bovine herpesvirus 1, bovine herpesvirus 4, foot-and-mouth disease virus, and parainfluenza 3 virus have been isolated from milk from cows with clinical mastitis. Intramammary inoculations of bovine herpesvirus 1 or parainfluenza 3 virus-induced clinical mastitis, while an intramammary inoculation of foot-and-mouth disease virus resulted in necrosis of the mammary gland. Subclinical mastitis has been induced after a simultaneous intramammary and intranasal inoculation of lactating cows with bovine herpesvirus 4. Bovine leukaemia virus has been detected in mammary tissue of cows with subclinical mastitis, but whether this virus was able to induce bovine mastitis has not been reported. Bovine herpesvirus 2, vaccinia, cowpox, pseudocowpox, vesicular stomatitis, foot-and-mouth disease viruses, and bovine papillomaviruses can play an indirect role in the aetiology of bovine mastitis. These viruses can induce teat lesions, for instance in the ductus papillaris, which result in a reduction of the natural defence mechanisms of the udder and indirectly in bovine mastitis due to bacterial pathogens. Bovine herpesvirus 1, bovine viral diarrhoea virus, bovine immunodeficiency virus, and bovine leukaemia virus infections may play an indirect role in bovine mastitis, due to their immunosuppressive properties. But, more research is warranted to underline their indirect role in bovine mastitis. We conclude that viral infections can play a direct or indirect role in the aetiology of bovine mastitis; therefore, their importance in the aetiology of bovine mastitis and their economical impact needs further attention.     

Bacterial zoonoses of fishes: A review and appraisal of evidence for linkages between fish and human infections

Human contact with and consumption of fishes presents hazards from a range of bacterial zoonotic infections. Whereas many bacterial pathogens have been presented as fish-borne zoonoses on the basis of epidemiological and phenotypic evidence, genetic identity between fish and human isolates is not frequently examined or does not provide support for transmission between these hosts. In order to accurately assess the zoonotic risk from exposure to fishes in the context of aquaculture, wild fisheries and ornamental aquaria, it is important to critically examine evidence of linkages between bacteria infecting fishes and humans. This article reviews bacteria typically presented as fish-borne zoonoses, and examines the current strength of evidence for this classification. Of bacteria generally described as fish-borne zoonoses, only Mycobacterium spp., Streptococcus iniae, Clostridium botulinum, and Vibrio vulnificus appear to be well-supported as zoonoses in the strict sense. Erysipelothrix rhusiopathiae, while transmissible from fishes to humans, does not cause disease in fishes and is therefore excluded from the list. Some epidemiological and/or molecular linkages have been made between other bacteria infecting both fishes and humans, but more work is needed to elucidate routes of transmission and the identity of these pathogens in their respective hosts at the genomic level.     

Epidemiology and control of trematode infections in cattle in Zimbabwe: a review

In this paper the main epidemiological aspects of the major domestic ruminant trematode infections in Zimbabwe are reviewed and discussed with regard to the available options for control. Seasonal occurrence of amphistomes, Fasciola gigantica and Schistosoma mattheei are considered both in the definitive and intermediate hosts. The regional distribution of the trematodes is reviewed in relation to the distribution patterns of their snail intermediate hosts. Based on the epidemiological features of the trematodes, practical control measures are suggested.     

Columnaris disease in fish: a review with emphasis on bacterium-host interactions

Flavobacterium columnare (F. columnare) is the causative agent of columnaris disease. This bacterium affects both cultured and wild freshwater fish including many susceptible commercially important fish species. F. columnare infections may result in skin lesions, fin erosion and gill necrosis, with a high degree of mortality, leading to severe economic losses. Especially in the last decade, various research groups have performed studies aimed at elucidating the pathogenesis of columnaris disease, leading to significant progress in defining the complex interactions between the organism and its host. Despite these efforts, the pathogenesis of columnaris disease hitherto largely remains unclear, compromising the further development of efficient curative and preventive measures to combat this disease. Besides elaborating on the agent and the disease it causes, this review aims to summarize these pathogenesis data emphasizing the areas meriting further investigation.     

Mycobacterium marinum infection in fish and man: epidemiology,pathophysiology and management; a review

Mycobacterium marinum is an opportunistic pathogen inducing infection in fresh and marine water fish. This pathogen causes necrotizing granuloma like tuberculosis, morbidity and mortality in fish. The cell wall-associated lipid phthiocerol dimycocerosates, phenolic glycolipids and ESAT-6 secretion system 1 (ESX-1) are the conserved virulence determinant of the organism. Human infections with Mycobacterium marinum hypothetically are classified into four clinical categories (type I–type IV) and have been associated with the exposure of damaged skin to polluted water from fish pools or contacting objects contaminated with infected fish. Fish mycobacteriosis is clinically manifested and characterized in man by purple painless nodules, liable to develop into superficial crusting ulceration with scar formation. Early laboratory diagnosis of M. marinum including histopathology, culture and PCR is essential and critical as the clinical response to antibiotics requires months to be attained. The pathogenicity and virulence determinants of M. marinum need to be thoroughly and comprehensively investigated and understood. In spite of accumulating information on this pathogen, the different relevant data should be compared, connected and globally compiled. This article is reviewing the epidemiology, virulence factors, diagnosis and disease management in fish while casting light on the potential associated public health hazards.     

Cryptosporidium infections in man, animals, birds and fish

SUMMARY: The protozoan parasite Cryptosporidium has gained better recognition over the last decade as an enteropathogen in a wide variety of host animals. Prior to 1975, infections were thought to occur infrequently and to be largely asymptomatic in nature. However, recent studies have revealed the organism to be more prevalent and pathogenic than previously thought. Infections producing clinical disease have been recorded in numerous host species including man, and the organism is now regarded as a newly-emergent zoonosis. This paper collates information currently available on the host range and specificity, life cycle and pathogenicity of the parasite and summarises the various techniques used to diagnose infections. Aust. vet. J. 62: 253–258     

Bulk milk ELISA and the diagnosis of parasite infections in dairy herds: a review

The bulk milk enzyme-linked immune sorbent assay (ELISA) is a rapid and inexpensive method of assessing herd exposure to pathogens that is increasingly being used for the diagnosis of parasite infections in dairy herds. In this paper, with the dairy herd health veterinarian in mind, we review the principles of the assay and the recent literature on the potential role of bulk milk ELISA for the diagnosis of ostertagiosis, fasciolosis, parasitic bronchitis due to cattle lung worm and neosporosis. It is generally accepted that assay results reflect exposure to the parasite rather than the presence of active infection. Bulk milk ELISA can be a useful tool for the veterinary practitioner as a component of a herd health monitoring programme or in the context of a herd health investigation. It can also play a role in regional or national surveillance programmes. However, the results need to be interpreted within the context of the herd-specific health management, the milk production pattern and the parasite life cycle.     

Prevention and surveillance of surgical infections: A review

Optimal patient care cannot be realized without effectively managing risks related to healthcare‐associated infections (HAI). Among human hospital admissions in the United States in 2002, there were approximately 4.5 HAI per 100 admissions, with surgical site infections (SSI) accounting for an estimated 20%, or approximately 2 SSI per 100 procedures. When considering the occurrence of disease in a population, it is important to remember that disease does not occur randomly in populations. Therefore, when thinking about managing risks associated with the occurrence of SSI, consideration should be given to key factors in disease development (the agent, the host, and the environment), and a multifaceted approach to prevention efforts should be considered, including the identification of high‐risk populations, adherence to aseptic principles, judicious use of antimicrobial drugs, and surveillance targeting SSI to better inform infection control practices within a facility. Although not all HAI are preventable, it is important to focus efforts on the preventable fraction and to take all reasonable precautions to mitigate foreseeable risks.     

Streptococcus gallolyticus infections in racing pigeons, a literature review

S. gallolyticus, formerly known as S. bovis is known since 1988 as a facultative pathogen of racing pigeons. Important clinical signs include acute mortality, inability to fly, lameness, weight loss and slimy green diarrhea. A pathognomonic sign at post mortem examination is the presence of well circumscribed areas of necrosis in the pectoral muscle. Furthermore tenosynovitis of the supracoracoid muscle and arthritis of the knee, shoulder and hock can be observed. In one study S. gallolyticus septicaemia was diagnosed in 10% of necropsied pigeons. Since S. gallolyticus was also isolated from nearly 40% of clinical healthy pigeons it is regarded as a facultative pathogen. Various biotypes, serotypes and culture supernatant phenotypes can be distinguished. Supernatant phenotypes are identified on the basis of the presence of either a T1, T2 or T3 protein triplet and the presence or absence of an extracellular A protein. S. gallolyticus strains with A protein are highly virulent, while strains with only T3 or T2 protein are of moderately or low virulence respectively. Fimbriae are only seen in highly virulent and some of the moderately virulent strains. Possible virulence factors include survival in macrophages, adhesion to cells and toxin production. Infection with serotype 1 and 2 induces some degree of protection against re-infection with serotype 1, which offers perspectives for the development of a vaccine. Experimentally ampicillin, doxycycline and erythromycin have shown therapeutic effects. For the treatment of clinical cases the use of ampicillin is advocated, together with hygienic measures, such as the use of grid floors and avoiding overcrowding.     

New trends in parasitic infections of cultured freshwater fish

The 1980s are characterized by the appearance of new fish parasitoses, the clarification of the aetiology of diseases and new insights into the process of infection and the development of important parasites, especially myxosporidians. Two phaerosporoses have entered into the foreground: swimbladder inflammation (SBI) caused by Sphaerospora renicola in common carp and proliferative kidney disease (PKD) in salmonids. Both diseases must be reported in the German Democratic Republic (GDR). The connection between the "C-protozoa" in the blood and S. renicola in SBI was recently clarified by experiments by Molnar (1988). The results of our own investigations indicate that the "K-protozoa" phase of S. renicola parasitizes mainly the brain and sometimes the spleen, pancreas and liver before appearing in the swimbladder. Hedrick et al. (1988) in the USA and Odening et al. (1988b) in Europe first reported a Sphaerospora sp. in Salmo gairdneri in connection with PKD. The spectacular findings by Wolf and Markiw (1984) and El-Matbouli (1988) elucidating on the life cycle of Myxobolus cerebralis have not yet brought the revolutionary change expected for a general new estimation of myxosporidian transmission as a basis for ecotechnological control measures. Examples for the formation of new regionally specific parasite colonizations offer the far Eastern cyprinids introduced into Europe. In the GDR the silver carp is infected by Chloromyxum barbi (Myxosporidia) (Sedlazsek), the pathogenic Gyrodactylus sprostonae and two new Gyrodactylus species (Pectobathrii) (Lux). Eel parasites new to Europe are the obviously imported and highly pathogenic nematodes Anguillicola crassus and A. novaezelandiae (Paggi et al., 1982; Moravec and Taraschewski, 1988). In Central Europe the infestation of rainbow trout by the tapeworm Proteocephalus neglectus is increasing (Priemer, 1980; Hanzelova et al., 1988).     

Piscine mycobacteriosis: a literature review covering the agent and the disease it causes in fish and humans

Mycobacterium marinum, M. fortuitum and M. chelonae are the etiological agents of fish mycobacteriosis. Fish mycobacteriosis is a disseminated infection reported in more than 150 fish species and is usually accompanied by emaciation and death over a period of months to years. Granulomas are formed both externally and scattered throughout the internal organs. Treatment is in most cases unsatisfactory and the overall recommendation is to destroy the diseased stock, particularly since these pathogens are capable of affecting man as well as fish. Especially fish handlers and aquarium hobbyists are infected and the disease is mostly confined to the superficial, cooler body tissues, most often the extremities. Dissemination is apparently rare but has been reported.     

Diagnosis o Yersinia enterocolitica infections: a review on classical identification techniques and new molecular biological methods

Only three of the eleven species of the genus Yersinia are associated with disease. Y. pestis is the causative agent of plague, Y. pseudotuberculosis and several pathogenic bio/serovars of the species Y. enterocolitica cause yersiniosis. New Y. enterocolitica subspecies with diagnostic relevance have been proposed allowing the differentiation of European and American isolates. The ISO-standard (ISO 102739) summarizes the knowledge gained from enrichment and isolation of Y. enterocolitica from food and feed samples. The final biochemical identification must be carried out by classical tube testing, as commercially available test-systems are not sensitive and specific. For the assessment of the presumptive pathogenicity of a Y. enterocolitica isolate empiric virulence markers can be replaced by PCR assays targeting plasmoidal or chromosomal genes. Their evaluation in terms of routine diagnostic procedures is still missing. The definite identification of Y. enterocolitica isolates can also be achieved by sequencing the 16S rRNA gene. Immunoblot based on plasmoidal encoded Yersinia proteins enables the serological determination of animal and human infections. The development of simple, sensitive and specific rapid identification systems applicable for the direct and indirect diagnosis for veterinary use is a challenge for the future.     

Filaroides osleri (Oslerus osleri): two case reports and a review of canid infections in North America

Infections of domesticated dogs by a worldwide parasitic nematode Filaroides osleri (Oslerus osleri) lead to verminous tracheobronchitis that are often misdiagnosed clinically as kennel cough, due to infection with the bacterium Bordetella bronchiseptica. Diagnosis of two canine cases in Wyoming, USA prompted a search of the literature of canid infections in North America. Infections of domestic dogs are reported in nine US states and four Canadian provinces. Dogs of multiple breeds and both sexes were infected. Most were two years old or younger at diagnosis. Anthelmintic treatments were effective in relieving clinical symptoms, as well as causing resolution of tracheobronchial nodules. Other canid species, including coyotes (Canis latrans) and wolves (Canis lupus), have been infected across North America with a prevalence of 23% and 4%, respectively. Infection with F. osleri should be included in the differential diagnosis of infectious tracheobronchitis of dogs. It can be confirmed most readily by endoscopic detection of distinctive submucosal parasite-filled nodules, combined with histological examination of endoscopic biopsies.