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Malone CJ, Oksanen A, Mukaratirwa S, Sharma R, Jenkins E. From wildlife to humans: The global distribution of Trichinella species and genotypes in wildlife and wildlife-associated human trichinellosis. Int J Parasitol Parasites Wildl 2024; 24:100934. [PMID: 38651034 PMCID: PMC11033181 DOI: 10.1016/j.ijppaw.2024.100934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 04/02/2024] [Accepted: 04/02/2024] [Indexed: 04/25/2024]
Abstract
Zoonotic nematodes of the genus Trichinella are foodborne parasites that have a global distribution in wild carnivores and omnivores, with spillover and spillback into domestic livestock and people, with concomitant trade and health consequences. Historically, most human cases were linked to domestic pigs infected with Trichinella spiralis, but under current high biosecurity swine production in many countries, wildlife have become a more important source of human trichinellosis. The aim of this review is to update the global distribution of Trichinella species and genotypes reported in wildlife, as well as reported human outbreaks from the consumption of wildlife. Using several online databases and by "snowballing" references, hundreds of reports of Trichinella spp. in wildlife published between January 1991 and December 2023 provide an important update to the host and geographic range for each of the recognized 13 species/genotypes, grouped by continent. Surveillance effort was highest in Europe and North America, while Africa, Asia, Central and South America have had limited surveillance, in some instances with human cases serving as sentinels of transmission in a region. Dozens of human outbreaks are described, with wild boars (Sus scrofa) being the most frequently implicated wildlife species in human outbreaks globally. Bears are an important source of infection in North America, for wildlife tourism, and importation of bear meat has also been implicated in multicountry outbreaks. The largest study limitation was the dearth of molecular identification of larvae in both wildlife surveillance studies and human outbreaks, particulary in under-studied regions. We highlight the need for enhanced molecular epidemiological approaches to outbreaks of this important foodborne parasite, and emphasize the need for a One Health approach to manage Trichinella spp. which transmit among terrestrial and marine wildlife (including migratory birds), pigs, horses, and people, often across large geographic scales and borders.
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Affiliation(s)
- Cody J. Malone
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Antti Oksanen
- Finnish Food Authority, (FINPAR), Elektroniikkatie 3, FI-90590, Oulu, Finland
| | - Samson Mukaratirwa
- One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Rajnish Sharma
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Centre for One Health, College of Veterinary Science, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, Punjab, India
| | - Emily Jenkins
- Department of Veterinary Microbiology, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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Mixed Infection of Mycobacterium szulgai, M. lentiflavum, and Gram-Negative Nacteria as a Cause of Death in a Brown Caiman Caiman crocodylus: A Case Report. Vet Sci 2022; 9:vetsci9030133. [PMID: 35324861 PMCID: PMC8949478 DOI: 10.3390/vetsci9030133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 02/01/2023] Open
Abstract
This paper describes a fatal case of nontuberculosis mycobacteriosis in a four-year-old brown caiman kept in captivity. Although the clinical signs were asymptomatic, severe gross lesions were observed, namely necrotic inflammation of the intestines and granulomatous hepatitis. Microbiological and histopathological examination performed on the tissues collected postmortem revealed a mixed infection of Mycobacterium lentiflavum and Mycobacterium szulgai, secondarily mimicked with Salmonella Coeln, Aeromonas hydrofila, Citrobacter freundii, and Providencia rettgeri. Those microorganisms are not only potentially pathogenic to reptiles, but also have a zoonotic importance for humans. Our findings clearly demonstrate the importance of educating owners and maintaining hygiene rules when handling reptiles.
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La Grange LJ, Mukaratirwa S. Epidemiology and hypothetical transmission cycles of Trichinella infections in the Greater Kruger National Park of South Africa: an example of host-parasite interactions in an environment with minimal human interactions. Parasite 2020; 27:13. [PMID: 32163031 PMCID: PMC7067144 DOI: 10.1051/parasite/2020010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 02/24/2020] [Indexed: 01/20/2023] Open
Abstract
Knowledge on the epidemiology, host range and transmission of Trichinella spp. infections in different ecological zones in southern Africa including areas of wildlife-human interface is limited. The majority of reports on Trichinella infections in sub-Saharan Africa were from wildlife resident in protected areas. Elucidation of the epidemiology of the infections and the prediction of hosts involved in the sylvatic cycles within specific ecological niches is critical. Of recent, there have been reports of Trichinella infections in several wildlife species within the Greater Kruger National Park (GKNP) of South Africa, which has prompted the revision and update of published hypothetical transmission cycles including the hypothetical options based previously on the biology and feeding behaviour of wildlife hosts confined to the GKNP. Using data gathered from surveillance studies and reports spanning the period 1964-2019, confirmed transmission cycles and revised hypothesized transmission cycles of three known Trichinella species (T. zimbabwensis, Trichinella T8 and T. nelsoni) are presented. These were formulated based on the epidemiological factors, feeding habits of hosts and prevalence data gathered from the GKNP. We presume that the formulated sylvatic cycles may be extrapolated to similar national parks and wildlife protected areas in sub-Saharan Africa where the same host and parasite species are known to occur. The anecdotal nature of some of the presented data confirms the need for more intense epidemiological surveillance in national parks and wildlife protected areas in the rest of sub-Saharan Africa to unravel the epidemiology of Trichinella infections in these unique and diverse protected landscapes.
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Affiliation(s)
- Louis J. La Grange
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Department of Agriculture, Rural Development, Land and Environmental Affairs, Chief Directorate Veterinary Services, Veterinary Public Health Private Bag X11309 Mbombela 1200 South Africa
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University of KwaZulu-Natal, School of Life Sciences, Westville Campus Durban 4000 South Africa
| | - Samson Mukaratirwa
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University of KwaZulu-Natal, School of Life Sciences, Westville Campus Durban 4000 South Africa
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One Health Center for Zoonoses and Tropical Veterinary Medicine, Ross University School of Veterinary Medicine P.O. Box 334 St Kitts Basseterre West Indies
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Segwagwe BE, Machete J, Ntwaetsile M, Mushonga B, Kandiwa E. No evidence of Trichinella spp. in domestic pig carcasses at a selected abattoir in southern Botswana. Trop Anim Health Prod 2018; 51:1273-1275. [PMID: 30105598 DOI: 10.1007/s11250-018-1684-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/03/2018] [Indexed: 10/28/2022]
Abstract
Trichinellosis is a worldwide zoonosis with genotypes affecting different domestic and wild animals and is widely distributed throughout the world. Species and genotypes of this genus affecting different animals have been identified. Despite its occurrence in Sub-Saharan countries, the presence of trichinellosis in Botswana is yet to be confirmed. The objective of this study was to determine the prevalence of Trichinella infection in domestic pigs slaughtered at an abattoir in Gaborone, Botswana. Of the 111 pig carcasses selected, 5 g of crus of the diaphragm was collected from each carcass, trimmed of all fat and fascia and then cut into 1- to 2-g samples. The muscle samples were pooled into 100-g muscle sample and then processed by the OIE prescribed digestion method. A stereomicroscope was used to examine each grid of the Petri dish for the presence of Trichinella larvae. No Trichinella larvae were found in any digested muscle samples. Future studies should target a wider pig population and other host animals.
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Affiliation(s)
- Basiamisi Ernest Segwagwe
- Department of Biomedical Sciences, Faculty of Medicine, University of Botswana, P. Bag UB0074, Gaborone, Botswana.
| | - James Machete
- Department of Animal Science and Production, Botswana University of Agriculture and Natural Resources, Private Bag 0027, Gaborone, Botswana
| | - Mpho Ntwaetsile
- Department of Animal Science and Production, Botswana University of Agriculture and Natural Resources, Private Bag 0027, Gaborone, Botswana
| | - Borden Mushonga
- Department of Biomedical Sciences, School of Veterinary Medicine, Faculty of Agriculture and Natural Resources, University of Namibia, P. Bag 13301, Pioneerspark, Windhoek, Namibia
| | - Erick Kandiwa
- Department of Biomedical Sciences, School of Veterinary Medicine, Faculty of Agriculture and Natural Resources, University of Namibia, P. Bag 13301, Pioneerspark, Windhoek, Namibia
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Abstract
Cardiovascular diseases are widely distributed throughout the world. Human parasitic infections are ubiquitous. Tropical parasites are increasingly recognized as causes of cardiovascular diseases. In this review, we address the most frequently reported parasites that directly infect the myocardium, including Trypanosoma cruzi, the protozoal causative agent of American trypanosomiasis (Chagas disease), and Taenia solium, the cestode causative agent of taeniasis and cysticercosis. We also discuss tropical endomyocardial fibrosis, trichinellosis and schistosomiasis. Health systems, attitudes, the perceptions of both patients and physicians as well as socioeconomic factors should all be explored and recognized as crucial factors for improving the control of cardiovascular diseases in the tropics. Clinicians throughout the world must remain aware of imported parasites as potential causes of cardiac diseases.
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Affiliation(s)
- Zoe C Groom
- Costello Medical Consulting Limited, Cambridge
| | | | - Vasileios Zochios
- Department of Intensive Care Medicine, Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust
- College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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Roesel K, Nöckler K, Baumann MPO, Fries R, Dione MM, Clausen PH, Grace D. First Report of the Occurrence of Trichinella-Specific Antibodies in Domestic Pigs in Central and Eastern Uganda. PLoS One 2016; 11:e0166258. [PMID: 27870858 PMCID: PMC5117603 DOI: 10.1371/journal.pone.0166258] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/25/2016] [Indexed: 11/18/2022] Open
Abstract
Previous research on trichinellosis in Africa focused on isolating Trichinella from wildlife while the role of domestic pigs has remained highly under-researched. Pig keeping in Uganda is historically recent, and evidence on zoonotic pig diseases, including infection with Trichinella species, is scarce. A cross-sectional survey on Trichinella seroprevalence in pigs was conducted in three districts in Central and Eastern Uganda from April 2013 to January 2015. Serum from a random sample of 1125 pigs from 22 villages in Eastern and Central Uganda was examined to detect immunoglobulin G (IgG) against any Trichinella spp. using a commercially available ELISA based on excretory-secretory antigen. ELISA positive samples were confirmed using Western Blot based on somatic antigen of Trichinella spiralis as recommended in previous validation studies. Diaphragm pillar muscle samples (at least 5 g each) of 499 pigs from areas with high ELISA positivity were examined using the artificial digestion method. Overall, 78 of all 1125 animals (6.9%, 95% CI: 5.6-8.6%) tested positive for antibodies against Trichinella spp. in the ELISA at significantly higher levels in Kamuli district compared to Masaka and Mukono districts. Thirty-one percent of the ELISA positive samples were confirmed IgG positive by the Western Blot leading to an overall seroprevalence of 2.1% (95% CI: 1.4-3.2%). The large proportion of ELISA positive samples that could not be confirmed using Western blot may be the result of cross-reactivity with other gastrointestinal helminth infections or unknown host-specific immune response mechanisms in local pig breeds in Uganda. Attempts to isolate muscle larvae for species determination using the artificial digestion method were unsuccessful. Due to the large number of muscle samples examined we are confident that even if pigs are infected, the larval burden in pork is too low to pose a major risk to consumers of developing trichinellosis. This was the first large systematic field investigation of Trichinella infection in domestic pigs in Uganda and its results imply that further studies are needed to identify the Trichinella species involved, and to identify potential sources of infection for humans.
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Affiliation(s)
- Kristina Roesel
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- Food safety and zoonoses program, International Livestock Research Institute, Nairobi, Kenya
- * E-mail:
| | - Karsten Nöckler
- Department Biological Safety, Federal Institute for Risk Assessment, Berlin, Germany
| | - Maximilian P. O. Baumann
- FAO Reference Centre for Veterinary Public Health, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Reinhard Fries
- Institute for Meat Hygiene, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Michel M. Dione
- Animal science for sustainable productivity program, International Livestock Research Institute, Kampala, Uganda
| | - Peter-Henning Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Delia Grace
- Food safety and zoonoses program, International Livestock Research Institute, Nairobi, Kenya
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7
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Differential immune responses in mice infected with the tissue-dwelling nematode Trichinella zimbabwensis. J Helminthol 2015; 90:547-54. [PMID: 26294082 DOI: 10.1017/s0022149x15000723] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
To improve diagnostic tools, immunotherapies and vaccine development for trichinellosis surveillance and control there is a need to understand the host immune responses induced during infection with Trichinella zimbabwensis, a tissue-dwelling nematode. In this study, we sought to determine immune responses induced in mice during T. zimbabwensis infection. The parasite strain used (Code ISS1209) was derived from a naturally infected crocodile (Crocodylus niloticus) and is the main Trichinella species prevalent in southern Africa. Sixty 6- to 8-week-old female BALB/c mice were randomly assigned to two equal groups: T. zimbabwensis-infected (n= 30) and the non-infected control group (n= 30). Levels of serum tumour necrosis factor-alpha (TNF-α), interleukin-10 (IL-10), interleukin-4 (IL-4) as well as parasite-specific IgM, IgG, IgG1, IgG2a, IgG2b and IgG3 antibody responses were determined using enzyme-linked immunosorbent assay (ELISA). The cytokines and antibodies provided information on T-helper 1 (Th1)- and Th2-type, T-regulatory and antibody responses. Results showed that during the intestinal stage of infection, higher levels of parasite-specific IgM, IgG, IgG1 (P < 0.05) and IL-10 and TNF-α (P < 0.001) were observed in the Trichinella-infected group compared with the non-infected control group. In the parasite establishment and tissue migration phases, levels of IgG1 and IgG3 were elevated (P < 0.001), while those of IgM (P < 0.01) declined on days 21 and 35 post infection (pi) compared to the enteric phase. Our findings show that distinct differences in Th1- and Th2-type and T-regulatory responses are induced during the intestinal, tissue migration and larval establishment stages of T. zimbabwensis infection.
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8
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La Grange LJ, Reininghaus B, Mukaratirwa S. First report of a mixed infection of Trichinella nelsoni and Trichinella T8 in a leopard (Panthera pardus) from the Greater Kruger National Park, South Africa. ACTA ACUST UNITED AC 2014; 81:e1-e3. [PMID: 25686214 DOI: 10.4102/ojvr.v81i1.836] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 09/05/2014] [Accepted: 09/05/2014] [Indexed: 11/01/2022]
Abstract
At least three Trichinella species, namely Trichinella nelsoni, Trichinella britovi and Trichinella zimbabwensis, and one genotype (Trichinella T8), have been isolated from sylvatic carnivores on the African continent. With the exception of T. britovi, the other species are known to circulate in wildlife of the Kruger National Park (KNP), South Africa, and KNP neighbouring game reserves (collectively known as the greater KNP area). Lions (Panthera leo) and spotted hyenas (Crocuta crocuta) appear to be the most important reservoirs of T. nelsoni and Trichinella T8 in the KNP and surrounding areas. Interspecies predation between lions and hyenas has been implicated as a primary mode of maintaining the life cycles of these two Trichinella species. This is the first report of a mixed natural infection of T. nelsoni and Trichinella T8 in a leopard (Panthera pardus) from South Africa. Trichinella muscle larvae were identified to species level by multiplex polymerase chain reaction (PCR). Probable sources of infection, based on the known dietary preference and prey species' range of leopards, are also discussed. The described occurrence of Trichinella species in a leopard from the greater KNP area raises the question of possible sources of infection for this predator species.
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Affiliation(s)
- Louis J La Grange
- Department of Agriculture, Rural Development, Land and Environmental Affairs, Mpumalanga, South Africa; School of Life Sciences, University of KwaZulu-Natal, Westville Campus, South Africa.
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Makanyanga TB, Mutema G, Mukarati NL, Chikerema SM, Makaya PV, Musari S, Matope G. Microbial quality of frozen Nile crocodile (Crocodylus niloticus) meat samples from three selected farms in Zimbabwe. Int J Food Microbiol 2014; 170:44-7. [PMID: 24291179 DOI: 10.1016/j.ijfoodmicro.2013.10.020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 08/15/2013] [Accepted: 10/26/2013] [Indexed: 11/25/2022]
Abstract
Microbial quality of frozen Nile crocodile (Crocodylus niloticus) meat from three farms in Zimbabwe was assessed based on 2051 samples collected for pre-export testing during 2006 to 2011. Data were perused by season and year in terms of aerobic plate (APC), coliform (CC), Escherichia coli (ECC) and Listeria monocytogenes (LMC) counts and the presence of Salmonella spp. The log10-transformed data were compared among the farms and seasons using the Kruskal-Wallis test. Microbial quality of the samples was graded based on the EC No. 2073.2005 criteria for beef. The mean APC and CC for the crocodile meat differed significantly (P=0.000) among the farms with the highest APC (3.2±0.05 log10 cfu/g) and the lowest (2.7±0.05 log10 cfu/g) recorded from farms A and C, respectively. There were no significant differences (P>0.05) in ECC and LMC among the farms, while Salmonella spp. were only isolated from one farm. Although the microbial quality of frozen crocodile meat from these farms was generally within acceptable limits, the isolation of E. coli and Salmonella spp. is of public health concern. Thus, implementing of measures to control the pasteurizing process and to minimize bacterial contamination of crocodile meat after pasteurization need to be carefully considered.
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Affiliation(s)
- Tsitsi B Makanyanga
- Department of Clinical Veterinary Studies, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Gideon Mutema
- Department of Clinical Veterinary Studies, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Norman L Mukarati
- Department of Clinical Veterinary Studies, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Sylvester M Chikerema
- Department of Clinical Veterinary Studies, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe
| | - Pious V Makaya
- Central Veterinary Laboratory, P.O. Box CY 551, Causeway, Harare, Zimbabwe
| | - Shuvai Musari
- Central Veterinary Laboratory, P.O. Box CY 551, Causeway, Harare, Zimbabwe
| | - Gift Matope
- Department of Paraclinical Veterinary Studies, University of Zimbabwe, P.O. Box MP 167, Mount Pleasant, Harare, Zimbabwe.
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10
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New pieces of the Trichinella puzzle. Int J Parasitol 2013; 43:983-97. [PMID: 23816802 DOI: 10.1016/j.ijpara.2013.05.010] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 05/27/2013] [Accepted: 05/29/2013] [Indexed: 11/22/2022]
Abstract
Contrary to our understanding of just a few decades ago, the genus Trichinella now consists of a complex assemblage of no less than nine different species and three additional genotypes whose taxonomic status remains in flux. New data and methodologies have allowed advancements in detection and differentiation at the population level which in turn have demonstrably advanced epidemiological, immunological and genetic investigations. In like manner, molecular and genetic studies have permitted us to hypothesise biohistorical events leading to the worldwide dissemination of this genus, and to begin crystalising the evolution of Trichinella on a macro scale. The identification of species in countries and continents otherwise considered Trichinella-free has raised questions regarding host adaptation and associations, and advanced important findings on the biogeographical histories of its members. Using past reviews as a backdrop, we have ventured to present an up-to-date assessment of the taxonomy, phylogenetic relationships and epidemiology of the genus Trichinella with additional insights on host species, survival strategies in nature and the shortcomings of our current understanding of the epidemiology of the genus. In addition, we have begun compiling information available to date on genomics, proteomics, transcriptomics and population studies of consequence in the hope we can build on this in years to come.
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Mukaratirwa S, La Grange L, Pfukenyi DM. Trichinella infections in animals and humans in sub-Saharan Africa: a review. Acta Trop 2013; 125:82-9. [PMID: 23041114 DOI: 10.1016/j.actatropica.2012.09.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 09/11/2012] [Accepted: 09/12/2012] [Indexed: 11/30/2022]
Abstract
The aim of this review is to provide information on Trichinella infection in humans, livestock and wildlife in sub-Saharan Africa mainly focusing on geographical distribution of species/genotypes, biology, host range, life cycles and to identify research gaps. Trichinella britovi, Trichinella nelsoni and Trichinella zimbabwensis and one genotype (Trichinella T8) are known to occur in sub-Saharan Africa. Distinct geographic ranges with overlapping of some taxa in some areas have been observed. Genetic variants of T. nelsoni has been reported to occur among parasites originating from Eastern and Southern Africa and sequence heterogeneity also occurs among T. zimbabwensis isolates originating from different regions of Zimbabwe and South Africa. Field observations so far indicate that sylvatic Trichinella infections in the region are common in carnivores (mammals and reptiles) and to a lesser extent in omnivores. Cannibalism, scavenging and predation appear to be the most important routes of transmission and maintenance of the sylvatic cycles of the Trichinella taxa. To date, human trichinellosis has been documented in only four sub-Saharan countries (8.7%, 4/46). Bushpigs and warthogs have been the source of human infection with T. britovi and T. nelsoni being the aetiological agents. An increase in bushmeat trade and the creation of Transfrontier Conservation Areas (TFCAs) may have increased the risk of human trichinellosis in the region. With the creation of TFCAs in the region, sampling of wildlife hosts from protected areas of most sub-Sahara African countries is required to fully map the distribution of Trichinella species/genotypes in this region. More structured field surveys are still needed to determine the sylvatic host distribution of the different Trichinella taxa. Biological data of the Trichinella taxa in both wild and domestic animals of sub-Saharan Africa is very limited and further research is required.
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Affiliation(s)
- Samson Mukaratirwa
- University of KwaZulu-Natal, School of Life Sciences, Westville Campus, Durban, South Africa.
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12
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The occurrence of Trichinella zimbabwensis in naturally infected wild crocodiles (Crocodylus niloticus) from the Kruger National Park, South Africa. J Helminthol 2012; 87:91-6. [PMID: 22335961 DOI: 10.1017/s0022149x12000089] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Trichinella zimbabwensis has been found naturally infecting crocodiles (Crocodylus niloticus) in Zimbabwe, Mozambique, Ethiopia and South Africa, as well as monitor lizards (Varanus niloticus) in Zimbabwe. The reports on natural infections were mostly accidental rather than structured surveys and involved very few animals. Previous surveillance studies in South Africa reported a 38.5% prevalence of T. zimbabwensis among wild crocodiles tested from the Mpumalanga province and Kruger National Park (KNP). No studies have been conducted to date on the geographical distribution and occurrence of T. zimbabwensis in wild crocodiles and varans in countries in southern Africa. Recent outbreaks of pansteatitis in crocodile populations of the KNP, South Africa, provided an opportunity to conduct a more structured survey aimed at elucidating the occurrence and distribution of T. zimbabwensis in culled wild crocodile populations within the KNP. Results from this study showed that T. zimbabwensis occurred in 10 out of 12 culled crocodiles form the KNP. The results also showed that the natural distribution of T. zimbabwensis in crocodiles includes all the major river systems in the KNP. The predilection sites of larvae in muscles followed a different pattern in naturally infected crocodiles compared to observations in experimentally infected mammalian hosts.
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Broglia A, Kapel C. Changing dietary habits in a changing world: Emerging drivers for the transmission of foodborne parasitic zoonoses. Vet Parasitol 2011; 182:2-13. [DOI: 10.1016/j.vetpar.2011.07.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Biological risks associated with consumption of reptile products. Int J Food Microbiol 2009; 134:163-75. [PMID: 19679367 DOI: 10.1016/j.ijfoodmicro.2009.07.001] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 06/25/2009] [Accepted: 07/04/2009] [Indexed: 11/22/2022]
Abstract
The consumption of a wide variety of species of reptiles caught from the wild has been an important source of protein for humans world-wide for millennia. Terrapins, snakes, lizards, crocodiles and iguanas are now farmed and the consumption and trade of their meat and other edible products have recently increased in some areas of the world. Biological risks associated with the consumption of products from both farmed and wild reptile meat and eggs include infections caused by bacteria (Salmonella spp., Vibrio spp.), parasites (Spirometra, Trichinella, Gnathostoma, pentastomids), as well as intoxications by biotoxins. For crocodiles, Salmonella spp. constitute a significant public health risk due to the high intestinal carrier rate which is reflected in an equally high contamination rate in their fresh and frozen meat. There is a lack of information about the presence of Salmonella spp. in meat from other edible reptilians, though captive reptiles used as pets (lizards or turtles) are frequently carriers of these bacteria in Europe. Parasitic protozoa in reptiles represent a negligible risk for public health compared to parasitic metazoans, of which trichinellosis, pentastomiasis, gnathostomiasis and sparganosis can be acquired through consumption of contaminated crocodile, monitor lizard, turtle and snake meat, respectively. Other reptiles, although found to harbour the above parasites, have not been implicated with their transmission to humans. Freezing treatment inactivates Spirometra and Trichinella in crocodile meat, while the effectiveness of freezing of other reptilian meat is unknown. Biotoxins that accumulate in the flesh of sea turtles may cause chelonitoxism, a type of food poisoning with a high mortality rate in humans. Infections by fungi, including yeasts, and viruses widely occur in reptiles but have not been linked to a human health risk through the contamination of their meat. Currently there are no indications that natural transmissible spongiform encephalopathies (TSEs) occur in reptilians. The feeding of farmed reptiles with non-processed and recycled animal products is likely to increase the occurrence of biological hazards in reptile meat. Application of GHP, GMP and HACCP procedures, respectively at farm and slaughterhouse level, is crucial for controlling the hazards.
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Abstract
Trichinella zimbabwensis has been detected in wild and farmed Nile crocodiles (Crocodylus niloticus) and in wild monitor lizards (Varanus niloticus) of several African countries, but it has never been detected in mammals in nature, in spite of its infectivity to rodents, pigs, foxes and monkeys under laboratory conditions. The aim of this work was to describe the first detection of T. zimbabwensis in a naturally infected lion (Panthera leo) of the Kruger National Park (KNP) of South Africa. The sequence of the expansion segment V, a highly variable non-coding sequence of the large subunit ribosomal RNA of the genus Trichinella, of larvae from the lion was identical to that of larvae of T. zimbabwensis collected from a Nile crocodile originating from the same locality as the lion, suggesting a possible transmission of this parasite between mammals and reptiles. The KNP proves to be a very interesting area for parasites of the genus Trichinella since three taxa (Trichinella nelsoni, Trichinella T8 and T. zimbabwensis) circulate among the wildlife of this protected area.
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La Grange LJ, Marucci G, Pozio E. Trichinella zimbabwensis in wild Nile crocodiles (Crocodylus niloticus) of South Africa. Vet Parasitol 2009; 161:88-91. [DOI: 10.1016/j.vetpar.2008.12.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 12/10/2008] [Accepted: 12/15/2008] [Indexed: 11/15/2022]
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Gottstein B, Pozio E, Nöckler K. Epidemiology, diagnosis, treatment, and control of trichinellosis. Clin Microbiol Rev 2009; 22:127-45, Table of Contents. [PMID: 19136437 PMCID: PMC2620635 DOI: 10.1128/cmr.00026-08] [Citation(s) in RCA: 472] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
SUMMARY Throughout much of the world, Trichinella spp. are found to be the causative agents of human trichinellosis, a disease that not only is a public health hazard by affecting human patients but also represents an economic problem in porcine animal production and food safety. Due to the predominantly zoonotic importance of infection, the main efforts in many countries have focused on the control of Trichinella or the elimination of Trichinella from the food chain. The most important source of human infection worldwide is the domestic pig, but, e.g., in Europe, meats of horses and wild boars have played a significant role during outbreaks within the past 3 decades. Infection of humans occurs with the ingestion of Trichinella larvae that are encysted in muscle tissue of domestic or wild animal meat. Early clinical diagnosis of trichinellosis is rather difficult because pathognomonic signs or symptoms are lacking. Subsequent chronic forms of the disease are not easy to diagnose, irrespective of parameters including clinical findings, laboratory findings (nonspecific laboratory parameters such as eosinophilia, muscle enzymes, and serology), and epidemiological investigations. New regulations laying down rules for official controls for Trichinella in meat in order to improve food safety for consumers have recently been released in Europe. The evidence that the disease can be monitored and to some extent controlled with a rigorous reporting and testing system in place should be motivation to expand appropriate programs worldwide.
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Affiliation(s)
- Bruno Gottstein
- Faculty of Medicine, Institute of Parasitology, University of Bern, Bern, Switzerland.
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Survival of Trichinella papuae muscle larvae in a pig carcass maintained under simulated natural conditions in Papua New Guinea. J Helminthol 2007; 81:429-32. [PMID: 18005466 DOI: 10.1017/s0022149x07850255] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In Papua New Guinea, Trichinella papuae, a non-encapsulated species, is circulating among wild and domestic pigs and saltwater crocodiles. Since an important phase of the life cycle of nematodes of the genus Trichinella is the time of survival of infective larvae in decaying muscle tissues of the hosts, the carcass of a pig, experimentally infected with larvae of T. papuae, was exposed to the environmental conditions of Papua New Guinea to establish how long these larvae would survive and remain infective to a new host. Larvae retained their infectivity in the pig carcass up to 9 days after slaughtering, during which time the temperature within the carcass reached 35.0 degrees C on 2 days; the average relative humidity was 79.0%. A low number of larvae survived up to day 14 after the pig was killed, when the carcass temperature reached 38.0 degrees C, but they lost their infectivity to laboratory mice. This result suggests that the larvae of T. papuae can survive in a tropical environment for a time, favouring their transmission to a new host in spite of the lack of a collagen capsule.
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Abstract
The etiological agents of human trichinellosis show virtually worldwide distribution in domestic and/or wild animals, with the exception of Antarctica, where the presence of the parasite has not been reported. This global distribution of Trichinella and varying cultural eating habits represent the main factors favouring human infections in industrialised and non-industrialised countries. Human trichinellosis has been documented in 55 (27.8%) countries around the world. In several of these countries, however, trichinellosis affects only ethnic minorities and tourists because the native inhabitants do not consume uncooked meat or meat of some animal species. Trichinella sp. infection has been documented in domestic animals (mainly pigs) and in wildlife of 43 (21.9%) and 66 (33.3%) countries, respectively. Of the 198 countries of the world, approximately 40 (20%) are small islands far from the major continents, or city-states where Trichinella sp. cannot circulate among animals for lack of local fauna (both domestic and wild). Finally, information on the occurrence of Trichinella sp. infection in domestic and/or wildlife is still lacking for 92 countries.
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Affiliation(s)
- Edoardo Pozio
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità, viale Regina Elena 299, 00161 Rome, Italy.
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