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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Approach to the Detection and Control of Foodborne Parasites and the Impact on Food Safety

Location: Animal Parasitic Diseases

2011 Annual Report


1a.Objectives (from AD-416)
Objective 1: Evaluate the impact of changing management and production practices (e.g. free range, confined, organic) on the incidence of Toxoplasmosis and Trichinella in swine, as it relates to foodborne risk.

Objective 2: Assess the effectiveness of on-farm interventions (such as passive immunization therapy as a feed supplement) to prevent enteric Toxoplasma infection in swine, consequent foodborne risk, and potential interaction with Salmonella foodborne infections in swine. C.1., PS 1B, and PS 1.D, Section 4.1. Objective 3: Evaluate the impact of anthelminthic and antiprotozoal treatments on parasitic foodborne infections in swine and the potential foodborne risk. Evaluate the impact of anthelminthic and antiprotozoal treatments on the interaction between foodborne pathogen and foodborne parasitic infections, specficially coinfections of Toxoplasma, Trichinella with Salmonaella and Campylobacter in swine, and changes following treatments. C.1., P.S., 1.A, and P.S., 1.D.


1b.Approach (from AD-416)
Toxoplasma gondii infects 11-20% of the U.S. population, causing birth defects in exposed pregnant women, devastating disease in immunocompromised individuals, and illness and loss of vision in otherwise healthy adults. Consumption of infected pork may be a significant source of infection for consumers in the U.S. Meat derived from pasture-raised pigs is of particular concern, since prevalence in these pigs may exceed 50%. Reducing the risk of foodborne human infection from meat requires adherence to livestock production practices that prevent exposure of animals to the parasite at the farm level, and the development of new treatments which can be used in pasture-raised pigs to prevent infection. Trichinella spiralis is a serious zoonotic pathogen with an unusually broad host and geographic range. Trichinella species infecting game animals pose a risk to humans consuming these meat products as well as a risk to domestic pigs that feed on their carcasses. Understanding the risk to pigs that have access to infected wildlife is an important component of on-farm certification efforts. In addition, the safety of meat from pasture-raised swine needs to be assessed in light of increasing consumer demand for organically-raised meat products. We will evaluate the impact of different management and production practices (e.g. free range, confinement, organically-raised pigs) on the incidence of Toxoplasma and Trichinella in swine, as it relates to foodborne risk, and assess the effectiveness of on-farm interventions (such as passive immunization therapy as a feed supplement) to prevent enteric Toxoplasma infection in swine, consequent foodborne risk, and potential interaction with Salmonella foodborne infections in swine.


3.Progress Report
The lab has evaluated the effect of 4 anthelminthic treatments on the viability of Trichinella spiralis muscle larvae in infected pigs. Isolated muscle larvae from levamisole, mebendazole, doramectin, and moxidectin treated pigs, and used larvae to infect mice. Only mebendazole treatment of pigs rendered muscle larvae non-viable. These data provide a means, especially for producers of high-risk, pasture raised swine, to eliminate the potential of Trichinella transmission from infected pork.

Conducted serological surveillance of 1,200 captured feral swine for Toxoplasma (seroprevalence ~20%) and Trichinella (seroprevalence ~3%), and tissue tested 300 feral swine for isolation and genotyping of Trichinella muscle larvae. For pigs that are raised outdoors, Trichinella may still pose a risk from co-mingling with infected feral swine. Recent legislation in the European Union endorses surveillance of wildlife indicator populations; this project provides data to establish feral swine as the indicator population.

Conducted quarterly training program for packer analysts for approved direct detection methods for T. spiralis in pork and horsemeat. Conducted testing of analysts and evaluated test results in consultation with the Animal and Plant Health Inspection Service (APHIS) and the Agricultural Marketing Service (AMS) to maintain integrity of the analyst training program.


4.Accomplishments
1. Investigated the effect of previous exposure of pigs to sylvatic genotypes of Trichinella on infection with T. spiralis. Infected pigs with T. nativa (T-2), T. pseudospiralis (T-4), and Trichinella murrelli (T-5), then challenged pigs with T. spiralis (T-1) to determine if a primary infection with sylvatic genotypes of Trichinella could protect pigs against a challenge infection with T. spiralis. Results demonstrated that previous exposure of pigs to the encapsulated genotypes occurring in North America was 96-100% protective against a challenge infection with T. spiralis. Initiated antibody isotype and microarray analysis of cytokine gene expression in blood and intestinal tissues to compare gene expression in immune vs susceptible animals.

2. Developed and implemented U.S. State Department funded Biosecurity Engagement Program on Trichinella spiralis in the Republic of the Philippines. In collaboration with the Bureau of Animal Industry, Philippine Animal Health Center (PAHC), Republic of the Philippines, established a validated Trichinella testing facility at PAHC, Quezon City, Luzon. Directed nationwide prevalence study for Trichinella spiralis in market hogs in the Philippines. Mutual laboratory visits were conducted for training of PAHC staff and sample collection in the field.


Review Publications
Houk, A.E., Goodwin, D.G., Zajac, A.M., Barr, S.C., Dubey, J.P., Lindsay, D.S. 2011. Prevalence of antibodies to Trypanosoma cruzi, Toxoplasma gondii, Encephalitozonn cuniculi, Sarcocystis neurona, Besnoitia darlingi, and Neospora caninum in North American opossum, Didelphis virginiana, from Southern Louisian. Journal of Parasitology. 96:1119-1122.

Vaudaux, J.D., Muccioli, C., James, E.R., Silveira, C., Jung, C., Dubey, J.P., Jones, J.L., Doymaz, D.A., Bruckner, D.A., Belfort, R., Holland, G.N., Grigg, M.E. 2010. Identification of an atypical strain of Toxoplasma gondii as the cause of a waterborne outbreak of toxoplasmosis in Santa IsabeldoIvai, Brazil. Journal of Infectious Diseases. 202:1226-1233.

Minervino, A.H., Soares, H.S., Barreto-Junior, R.A., Alessandri Loboneves, K., Pena, H.F., Dubey, J.P., Ortolani, J.L., Gennari, S.M. 2010. Seroprevalence of Toxoplasma gondii antibodies in captive wild mammals and birds in Brazil.. Journal of Zoo and Wildlife Medicine. 41:572-574.

Alvarado-Esquivel, C., Liesenfeld, O., Marquez-Conde, J.A., Estrada-Martinez, S., Dubey, J.P. 2010. Seroepidemiology of infection with Toxoplasma gondii in workers occupationally exposed to water, sewage, and soil in Durango, Mexico. 96:847-850.

Possenti, A., Cherchi, S., Pozio, E., Dubey, J.P., Spano, F. 2010. A family of cysteine-rich proteins is involved in the formation of the oocyst wall of Toxoplasma gondii. International Journal for Parasitology. 40:1639-1649.

Al-Kappany, Y., Rajendran, C., Ferreira, L., Kwok, O.C., Abu-Elwafa, S., Hilali, M., Dubey, J.P. 2010. High prevalence of toxoplasmosis in cats from Egypt: isolation of viable Toxoplasma Gondii, tissue distribution, and isolate designation. Journal of Parasitology. 96:1115-1118.

Al-Kappany, Y.M., Abu-Elwafa, S.A., Rajendran, C., Hilali, M., Su, C., Dubey, J.P. 2011. Genetic diversity of Toxoplama gondii isolates from cats from Egypt reveals new genotypes. Journal of Parasitology. 96:1112-1114.

Solorio, M.R., Gennari, S.M., Soares, H.S., Dubey, J.P., Powell, G., Ferreira, L. 2011. Toxoplasma gondii antibodies in wild white-lipped peccary (Tayassu pecari) from Peru. Journal of Parasitology. 96:1232.

Frazao-Teixeira, E., Sundar, N., Dubey, J.P., Grigg, M.E., De Oliveira, F.C.R. 2011. Multi-locus DNA sequencing of Toxoplasma gondii isolated from Brazilian pigs identifies genetically divergent strains. Veterinary Parasitology. 175:33-39.

Schares, G., Basso, W., Majzoub, M., Rostaher, A., Scharr, J.C., Langenmayer, M.C., Selmair, J., Dubey, J.P., Cortes, H.C., Conraths, F.J., Haupt, T., Raber, A., Buholzer, Gollnick, N.S., Purro, M. 2011. Evaluation of a commercial ELISA for the specific detection of antibodies against Besnoitia besnoiti. Veterinary Parasitology. 175:52-59.

Kulasena, V.A., Rajapakse, R.P., Dayawansa, P.N., Premawansa, S., Dubey, J.P. 2011. Seroprevalence of Toxoplasma gondii in cats from Colombo, Sri Lanka. Journal of Parasitology. 97:152.

Al-Kappany, Y.M., Lappin, M.R., Kwok, O.C., Abu-Elwafa, S.A., Hilali, M., Dubey, J.P. 2011. Seroprevalence of Toxoplasma gondii and concurrent Bartonella spp., feline immunodeficiency virus, feline leukemia virus, and Dirofilaria immitis infections in Egyptian cats. Journal of Parasitology. 97:256-258.

Houk, A.E., Rosypal, A.C., Grant, D.G., Dubey, J.P., Zajac, A.M., Yabsley, M.J., Lindsay, D.S. 2011. Serological response of cats to experimental Besnoitia darlingi and Besnoitia neotomofelis infections and prevalence of antibodies to these parasites in cats from Virginia and Pennsylvania. Journal of Parasitology. 97:259-261.

Hill, D.E., Coss, C., Dubey, J.P., Wroblewski, K., Sautter, M., Hosten, T., Munoz-Zanzi, C., Mui, E., Withers, S., Boyer, K., Hermes, G., Coyne, J., Jagdis, F., Burnett, A., Mccleod, P., Morton, H., Robinson, D., Mcleod, R. 2011. Identification of a sporozoite-specific antigen from Toxoplasma gondii. Journal of Parasitology. 97(2):328-337.

Dixon, B., Fayer, R., Santin, M., Hill, D.E., Dubey, J.P. 2011. Protozoan parisites: Cryptosporidium, Giardia, Cyclospora, and Toxoplasma. In: Hoorfar, J., editor. Foodborne Protozoans. Rapid Detection, Characterization, and Enumeration of Food-Borne Pathogens. Washington, D.C.: American Society for Microbiology. p. 349-370.

Khan, A., Dubey, J.P., Su, C., Ajioka, J.W., Rosenthal, B.M., Sibley, L.D. 2011. Genetic analyses of atypical Toxoplasma gondii strains reveals a fourth clonal lineage in North America. International Journal for Parasitology. 41:645-655.

Schares, G., Maksimov, A., Basso, W., More, G., Dubey, J.P., Rosenthal, B.M., Msjxoub, M., Rostaher, A., Selmair, J., Langenmayer, M.C., Scharr, J.C., Conraths, F.J., Gollnick, N.S. 2011. Quantitative real time polymerase chain reaction assays for the sensitive detection of Besnoitia besnoiti infection in cattle. Veterinary Parasitology. 178:208-216.

Lopes, A.P., Santos, H., Neto, F., Rodrigues, M., Kwok, O.C., Dubey, J.P., Carduso, L. 2011. Prevalence of antibodies to Toxoplasma gondii in dogs from northeastern Portugal. Journal of Parasitology. 97:418-420.

Alvarado-Esquivel, C., Urbina-Alvarez, E., Estrada-Martinez, S., Torres-Castorena, A., Molotla-De-Leon, G., Liesenfeld, O., Dubey, J.P. 2011. Toxoplasmosis gondii and schizophrenia: a case control study in a low Toxoplasma gondii seroprevalence Mexican population. Parasitology International. 60:151-155.

Cabezon, O., Hall, A.J., Vincent, C., Padon, M., Bocanegra, G., Dubey, J.P., Almeria, S. 2011. Seroprevalence of Toxoplasma gondii and Neospora caninum in north-eastern Atlantic Harbor seal. Veterinary Parasitology. 179:253-256.

Dubey, J.P., Felix, T.A., Kwok, O.C. 2010. Serological and parsitological prevalence of Toxoplasma gondii in wild birds from Colorado. Journal of Parasitology. 96:937-938.

Alvarado-Esquivel, C., Liesenfeld, O., Torres-Castorena, A., Estrada-Martínez, S., Urbina-Álvarez, J.D., Ramos-De La Rocha, M., Márquez-Conde, J.A., Dubey, J.P. 2010. Seroepidemiology of infection with Toxoplasma gondii in patients with vision and hearing impairments, cancer, HIV, or undergoing hemodialysis in Durango, Mexico. Journal of Parasitology. 96:505-506.

Alvarado-Esquivel, C., Pizarro-Villalobos, H., Arce-Quinones, M., Liesenfeld, O. 2011. Seroepidemiology of Toxoplasma gondii infection in general population in a Northern Mexican city. Journal of Parasitology. 97:40-43.

Last Modified: 10/20/2014
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