Zoonotic Aspects Research Articles

Trypanosoma evansi and surra: a review and perspectives on transmission, epidemiology and control, impact, and zoonotic aspects.

This paper reviews the transmission modes of Trypanosoma evansi. Its worldwide distribution is attributed to mechanical transmission. While the role of tabanids is clear, we raise questions on the relative role of Haematobia sp. and the possible role of Stomoxys sp. in delayed transmission. A review of the available trypanocidal drugs and their efficacy in various host species is useful for understanding how they interact in disease epidemiology, which is complex. Although there are similarities with other mechanically transmitted trypanosomes, T. evansi has a more complex epidemiology due to the diversity of its hosts and vectors. The impact of clinical and subclinical disease is difficult to establish. A model was developed for buffaloes in the Philippines, which could be transferred to other places and livestock systems. Since Trypanosoma evansi was reported in humans, further research is required to investigate its zoonotic potential. Surra remains a potentially emerging disease that is a threat to Australia, Spain, and France. A number of questions about the disease have yet to be resolved. This brief review of the basic knowledge of T. evansi suggests that there is renewed interest in the parasite, which is spreading and has a major economic impact.

Use of negative binomial distribution to describe the presence of Anisakis in Thyrsites atun

Nematodes of the genus Anisakis have marine fishes as intermediate hosts. One of these hosts is Thyrsites atun, an important fishery resource in Chile between 38 and 41° S. This paper describes the frequency and number of Anisakis nematodes in the internal organs of Thyrsites atun. An analysis based on spatial distribution models showed that the parasites tend to be clustered. The variation in the number of parasites per host could be described by the negative binomial distribution. The maximum observed number of parasites was nine parasites per host. The environmental and zoonotic aspects of the study are also discussed.

Dirofilarial Infections in Europe

Nematodes of the genus Dirofilaria are currently considered emerging agents of parasitic zoonoses in Europe. Climatic changes and an increase in the movement of reservoirs (mostly infected dogs) have caused an increase in the geographical range of these parasites from the traditionally endemic/hyperendemic southern regions, and the risk for human infection has increased. In the last several years, forecast models have predicted that current summer temperatures are sufficient to facilitate extrinsic incubation of Dirofilaria in many areas of Europe. The global warming projected by the Intergovernmental Panel on Climate Change suggests that warm summers suitable for Dirofilaria transmission in Europe will be the rule in the future decades, and if the actual trend of temperature increase continues, filarial infection should spread into previously infection-free areas. Dirofilaria repens is currently the filarial species that is most commonly reported as spreading from southern to northern areas. This article reviews the zoonotic aspects, effects of climate, and other global drivers on Dirofilaria infections in Europe and the possible implications on the transmission and control of these mosquito-borne nematodes.

Helicobacter suis KB1 derived from pig gastric lymphoid follicles induces the formation of gastric lymphoid follicles in mice through the activation of B cells and CD4 positive cells

“ Helicobacter heilmannii” (“ H. heilmannii”), which belongs to the genus Helicobacter, is a group of bacterial species that display a long spiral-shaped morphology. Recent studies have demonstrated that “ H. heilmannii” type 1 is actually H. suis, which mainly colonizes the stomachs of various animals and humans. However, the influence of H. suis on gastric diseases remains to be fully elucidated. In this report, we revealed the relationship between natural H. suis infection and follicular gastritis in the pig stomachs. From sequence analysis of the 16S rRNA, urease A, and urease B genes, the presence of H. suis was confirmed in pig gastric lymphoid follicles, and this bacterium was named H. suis KB1. In addition, H. suis KB1 was inoculated into C57BL/6J mice, and the following mouse model of the pathogenesis of follicular gastritis by H. suis infection was established: H. suis KB1 colonizes the mouse stomach, and moreover, induces the development of lymphoid follicles and acquired immune responses characterized by the activation of B cells and CD4 positive cells. These results may lead to better understanding of the relationship between H. suis and gastric diseases, especially follicular gastritis; and furthermore, our findings emphasize the zoonotic aspects of animal-human infection by H. suis.

Prevalence of Brucellosis in Horse North-East of Iran

Brucella preferentially infects cattle, swine, sheep, and goats. However, some epidemiological surveys have been carried out to investigate nonruminants, such as horses. Horse brucellosis has been found in clinical cases, but there are few epidemiologic patterns. Between May 2008 and April 2009, a total of 120 horses were screened for brucella infections in Mashhad, Iran, by the rose bengal test and the tube agglutination test. Sera from three horses were found positive by rose bengal test and tube agglutination test, and therefore the prevalence rate was 2.5%. In horses, the highest individual seroprevalence was in an animal kept close under the intensive system, with other animals such as cattle, sheep, and goats. The zoonotic aspects of brucellosis from the horse must, therefore, be considered because the disease is important from a public health standpoint. The present study documents the first serological evidence of Brucella spp. infection in horses in Iran.

Zoonoses of people and their pets: a US perspective on significant pet-associated parasitic diseases

Michael Paul, DVM is Executive Director, Companion Animal Parasite Council. Lonnie King, DVM is past-Director, National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Centers for Disease Control and Prevention, and current Professor and Dean of the College of Veterinary Medicine, The Ohio State University. Ellen P. Carlin, DVM is Special Projects Manager and Editor, Companion Animal Parasite Council.The findings and conclusions in this manuscript are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.

Epidemiologic and zoonotic aspects of ascarid infections in dogs and cats

Toxocaracanis and Toxocara cati of dogs and cats, respectively, can cause significant disease in people. Human seroprevalence for Toxocara antibodies varies with factors such as geographic location, socio-economic status, and dietary habits. Risk factors for infection include geophagia and low-level education. Toxocara canis is better recognized as a cause of human toxocariasis, but Toxocara cati should not be overlooked. In addition, patent infections with Baylisascaris procyonis, the raccoon ascarid, have been increasingly recognized in dogs. Pet owners need to be properly educated about zoonotic risks, and veterinarians should institute regular parasite screening and treatment for all pets. Establishment of national surveillance programs to determine the incidence and specific etiological agent in human larva migrans patients would aid in the development of targeted intervention strategies.

Feline Sporotrichosis in the Southern Region of Rio Grande Do Sul, Brazil: Clinical, Zoonotic and Therapeutic Aspects

Clinical cases of feline sporotrichosis, originating in the Pelotas region and diagnosed at the Laboratory of Infectious Diseases (UFPel), were studied in the period from 2002 to 2006. The animals were evaluated according to the clinical forms of the mycosis, time of lesion appearance, severity of the clinical diagnosis and evolution of cutaneous lesions throughout the treatment period. Mycological analyses, carried out through direct examination, cultivation of tissue samples and exudates of feline lesions all confirmed the diagnosis of sporotrichosis in the 15 animals under study. The cutaneous dissemination form was observed in 10 animals, of which three showed prostration, anorexia and dehydration. The zoonosis occurred in 20% of case studies, and the pet owners and one attendant at a veterinary clinic were infected, developing the fixed and disseminated cutaneous forms. The treatment of mycosis was carried out with itraconazole, 10 mg kg(-1), once a day, on 12 animals. The cure of the clinical symptoms was observed on 50% of the felines. This study demonstrates a good clinical response of felines with sporotrichosis, when they were treated itraconazole and calls the attention for the incidence of human sporotrichosis on people related to the veterinary activity as well as for pet owners.

Encephalomyocarditis virus

Encephalomyocarditis virus (EMCV) is a cardiovirus of Picornaviridae family. It has a word wide distribution and affects a wide range of domestic and wild animal species mainly rodents, pigs and non-human primates. Depending on the virus strain and the infected host, the virus can induce myocarditis, reproductive failure, diabetes or nervous disorders. The importance of EMCV as a cause of disease in humans is unknown. However, its wide host range and its biological characteristics make this virus a potential zoonotic agent. Furthermore, several direct and indirect arguments, suggest that human infections cannot be discarded. This review summarises the current knowledge on the molecular biology, the pathogenicity and the zoonotic aspects of this virus.

Clinical and zoonotic aspects of psittacosis

PSITTACOSIS is a common and potentially fatal bacterial disease of psittaciforms, which should be considered in any sick parrot presented at the clinic. It is also an important zoonosis and...

Zoonotic aspects of Mycobacterium bovis and Mycobacterium avium-intracellulare complex (MAC)

Pathogens that are transmitted between the environment, wildlife, livestock and humans represent major challenges for the protection of human and domestic animal health, the economic sustainability of agriculture, and the conservation of wildlife. Among such pathogens, the genus Mycobacterium is well represented by M. bovis, the etiological agent of bovine tuberculosis, M. avium ssp. paratuberculosis (Map) the etiological agent of Johne disease, M. avium ssp. avium (Maa) and in a few common cases by other emergent environmental mycobacteria. Epidemiologic surveys performed in Europe, North America and New Zealand have demonstrated the existence and importance of environmental and wildlife reservoirs of mycobacterial infections that limit the attempts of disease control programmes. The aim of this review is to examine the zoonotic aspects of mycobacteria transmitted from the environment and wildlife. This work is focused on the species of two main groups of mycobacteria classified as important pathogens for humans and animals: first, M. bovis, the causative agent of bovine tuberculosis, which belongs to the M. tuberculosis complex and has a broad host range including wildlife, captive wildlife, domestic livestock, non-human primates and humans; the second group examined, is the M. avium-intracellulare complex (MAC) which includes M. avium ssp. avium causing major health problems in AIDS patients and M. avium ssp. paratuberculosis the etiological agent of Johne disease in cattle and identified in patients with Crohn disease. MAC agents, in addition to a broad host range, are environmental mycobacteria found in numerous biotopes including the soil, water, aerosols, protozoa, deep litter and fresh tropical vegetation. This review examines the possible reservoirs of these pathogens in the environment and in wildlife, their role as sources of infection in humans and animals and their health impact on humans. The possibilities of control and management programmes for these mycobacterial infections are examined with regards to the importance of their natural reservoirs.

An update on avian influenza in poultry

The present paper reviews the worldwide situation regarding avian influenza (AI) infections caused by viruses of the H5 and H7 subtype in poultry from 1999 to date. The increase in the number of primary introductions and the scientific data available on the molecular basis of pathogenicity have generated concerns particularly for legislative purposes, for international trade and on novel control strategies, including vaccination. This has led to a new proposed definition of “avian influenza” to extend to all infections caused by H5 and H7 viruses regardless of their virulence as notifiable diseases, although this has encountered some difficulties in being approved. Reference is also made to the zoonotic aspects of avian influenza which until 1997 were considered to be of limited relevance in human medicine, and have now gained importance, both for illness and fatalities which have occurred following natural infection with avian viruses, and for the potential of generating a reassortant virus which could give rise to the next human influenza pandemic.

Brucellosis in Brazil

This paper reviews the epidemiology of bovine, swine, ovine, caprine, and canine brucellosis in Brazil. The zoonotic aspects of Brucella infection in Brazil is also discussed. Emphasis is given to the new program for the control of brucellosis in cattle and buffaloes that is likely to provide important insights into the prospects and strategies for controlling brucellosis in developing countries.

Chronic fatigue syndrome (CFS) associated with Staphylococcus spp. bacteremia, responsive to potassium arsenite 0.5% in a veterinary surgeon and his coworking wife, handling with CFS animal cases

Chronic fatigue syndrome (CFS) in human patients remain a controversial and perplexing condition with emerging zoonotic aspects. Recent advances in human medicine seem to indicate a bacterial etiology and the condition has already been described in horses, dogs, cats and birds of prey in association with micrococci-like organisms in the blood. To evaluate the possibility of a chronic bacteremia, a veterinary surgeon (the author) and his coworking wife, both diagnosed with CFS and meeting the CDC working case definition, were submitted to rapid blood cultures and fresh blood smears investigations. Blood cultures proved Staph-positive and micrococci-like organisms in the blood were repeatedly observed in the 3-year period preceding the arsenical therapy, during which several medicaments, including antibiotics, proved unsuccessful. Following treatment with a low dosage arsenical drug (potassium arsenite 0.5%, im., 1 ml/12 h, for 10 days) both patients experienced complete remission. At the post-treatment control made 1 month later, micrococci had disappeared from the blood, and the CD4/CD8 ratio was raising.

Borna disease virus: new aspects on infection, disease, diagnosis and epidemiology.

A 'disease of the head' affecting horses, as described in the 17th Century is now known as Borna disease. Research over the past 100 years has established that the aetiological agent, Borna disease virus (BDV), is an unsegmented, single- and negative-stranded, enveloped ribonucleic acid (RNA) virus which represents the family Bornaviridae in the order Mononegavirales. The virus exists world-wide in horses, sheep, cattle, cats, dogs and ostriches. The infection can be fatal, but the majority of carriers are persistently infected without showing symptoms. The association with psychiatric diseases in humans led to an international explosion of research on BDV, with centres established in Germany, the United States of America and Japan. Experimental infections of tree shrews and rats served to examine the effects of persistent and overt disease, most excitingly, virus-induced behavioural changes, and emotional and learning deficits. This 'emerging' virus infection shows complex pathogenetic mechanisms in the nervous system, but also spreads through myelo-monocytic cells. Diagnosis can be made serologically, but detection of antigen markers in peripheral white blood cells, combined with nucleic acid amplification is more profitable. Comparative RNA studies reveal an unusually high genetic homology of viruses. Isolates recovered from humans and equines suggest species-specificity. Vaccination is not an advisable strategy, but antiviral therapy, especially with amantadine sulphate, promises efficacy in human mood disorders, and is effective in vitro. Infections with BDV follow a vulnerability principle to cause disease. Although cross-species transmission of this commensal virus has not been proven, zoonotic aspects of BDV should be carefully considered.

Bacteriophage typing and serogrouping of Pseudomonas aeruginosa from animals.

Bacteriophage typing and serogrouping were carried out on 349 strains of Pseudomonas aeruginosa mainly from domestic animals. A new bacteriophage set for P. aeruginosa ‐ which had been developed entirely on the basis of human strains ‐ also worked satisfactorily in animal strains. The percentage of non‐typable strains isolated from animals was 7.9 as compared to 4.5 in a previous examination on 486 human strains. Part of this investigation was carried out on isolates with known herd relationships, such that reservoir and transmission could be evaluated. In several instances, humans had infections with pseudomonas of the same phage typing pattern and serogroup characteristics as simultaneously caused infections in cattle. The ubiquitous nature of P. aeruginosa as a pathogen was shown. This induces interesting hypotheses regarding the zoonotic aspects of pseudomonas infections. No particular phage types were characteristic for any particular animal species, or type, or site of infection—a finding which relates well with the omnipresence of pseudomonas. The serogroup 0:6 was the most frequent among bovine and musteline strains, but this is in accordance also with the high frequency thereof in strains of human origin. The most frequent phage typing pattern was 8, 12, 16 and related patterns (8; 8, 12; 12; 16; 8, 16; 12, 16) which together was found in approximately 1/3 of the isolates. The significance of milking equipment as a reservoir and a vector of infection was indicated by the occurrence of the same bacterial types from equipment and from udders.

Isolation and Identification of Bacteria from the Workers of Live Bird Markets at Mymensingh, Bangladesh

Context: Identification of bacteria from the workers of live bird markets is important factor for zoonotic aspects and for implementing appropriate control strategies.Objectives: To determine the occurrence of bacteria especially Salmonella sp. and Escherichia coli from the workers of live bird markets.Materials and Methods: A total of 40 samples were collected from hand washes (n=20) and nasal swabs (n=20) of the associated workers in urban and suburban live bird markets. Bacteria were isolated in different media, and identification was performed based on the staining, cultural and some biochemical tests. For Salmonella sp., DNA was extracted using a DNA isolation kit and rfbs gene was amplified by using commercial PCR kit.Results: The bacteria such as Salmonella sp. and E. coli were detected in the samples by several microbial tests. The prevalence of Salmonella sp. was 40% and 30%, and E. coli was 70% and 40% in the hand washes and nasal swabs respectively of the workers of urban and periurban live bird markets.Conclusion: The results obtained in this study suggest that the appropriate precautions should be taken during and subsequent to the handling of live birds to minimize the risk of zoonotic diseases.Key words: Salmonella; Escherichia coli; live bird markets; isolation and identificationDOI: 10.3329/jbs.v17i0.7121J. bio-sci. 17: 135-138, 2009