Food-borne Parasitic Zoonosis Research Articles

Characterization of Spirometra erinaceieuropaei Plerocercoid Cysteine Protease and Potential Application for Serodiagnosis of Sparganosis.

BackgroundSparganosis is a neglected but important food-borne parasitic zoonosis. Clinical diagnosis of sparganosis is difficult because there are no specific manifestations. ELISA using plerocercoid crude or excretory–secretory (ES) antigens has high sensitivity but has cross-reactions with other helminthiases. The aim of this study was to characterize Spirometra erinaceieuropaei cysteine protease (SeCP) and to evaluate its potential application for serodiagnosis of sparganosis.Methodology/Principal FindingsThe full length SeCP gene was cloned, and recombinant SeCP (rSeCP) was expressed and purified. Western blotting showed that rSeCP was recognized by the serum of sparganum-infected mice, and anti-rSeCP serum recognized the native SeCP protein of plerocercoid crude or ES antigens. Expression of SeCP was observed at plerocercoid stages but not at the adult and egg stages. Immunolocalization identified SeCP in plerocercoid tegument and parenchymal tissue. The rSeCP had CP activity, and the optimum pH and temperature were 5.5 and 37°C, respectively. Enzymatic activity was significantly inhibited by E-64. rSeCP functions to degrade different proteins and the function was inhibited by anti-rSeCP serum and E-64. Immunization of mice with rSeCP induced Th2-predominant immune responses and anti-rSeCP antibodies had the potential capabilities to kill plerocercoids in an ADCC assay. The sensitivity of rSeCP-ELISA and ES antigen ELISA was 100% when performed on sera of patients with sparganosis. The specificity of rSeCP-ELISA and ES antigen ELISA was 98.22% (166/169) and 87.57% (148/169), respectively (P<0.05).ConclusionsThe rSeCP had the CP enzymatic activity and SeCP seems to be important for the survival of plerocercoids in host. The rSeCP is a potential diagnostic antigen for sparganosis.

Trichinella britovi in a red fox (Vulpes vulpes) from Portugal

Trichinellosis is one of the most important foodborne parasitic zoonoses, caused by nematodes of the genus Trichinella. Pigs and other domestic and wild animals, including red foxes (Vulpes vulpes), are sources of Trichinella infection for human beings. Trichinella britovi is the major agent of infection in sylvatic animals and the most important species circulating in the European wildlife. The present study aimed at assessing Trichinella spp. infection in red foxes from the North of Portugal. Forty-seven carcasses of wild red foxes shot during the official hunting season or killed in road accidents were obtained between November 2008 and March 2010. In order to identify the presence of Trichinella spp. larvae in red foxes, an individual artificial digestion was performed using approximately 30g of muscle samples. Larvae of Trichinella spp. were detected in one (2.1%) out of the 47 assessed foxes. After a multiplex polymerase chain reaction analysis, T. britovi was molecularly identified as the infecting species. The recognition of T. britovi in a red fox confirms that a sylvatic cycle is present in the North of Portugal and that the local prevalence of Trichinella infection in wildlife must not be ignored due to its underlying zoonotic risks.

Progress in Treatment and Prevention of Trichinellosis

Trichinellosis is a foodborne parasitic zoonosis caused by eating raw or uncooked meat of animals infected with Trichinella species. The disease is widely distributed all over the world. It is a public health hazard by affecting humans and represents an economic problem in porcine animal production and food safety. Drugs used to treat Trichinellosis include anthelmintics and glucocorticosteroids. Benzimidazole derivatives or adding excipients, medical plant extracts and some biological agents have shown good insecticidal effects. Preventing infection is crucial for combating human and mammal trichinellosis. Designing effective vaccines and developing promising probiotics may be future preventive strategies against infection with Trichinella spiralis infection. This paper reviews new progress in the treatment and prevention of trichinellosis.

Paragonimus westermani infection in lung: A confounding diagnostic entity.

Paragonimiasis is a food-borne parasitic zoonosis caused by the genus Paragonimus. Fresh water snails, crabs, and crayfish are the first and second intermediate hosts, respectively. Humans acquire this infection by ingesting uncooked/undercooked crustaceans. Laboratory diagnosis of Paragonimiasis is done by demonstration of ova in the sputum/feces/pleural fluid or by serology. A case of pulmonary Paragonimiasis is presented herewith; the patient having been diagnosed with pulmonary tuberculosis earlier. The aim of this presentation is to highlight this entity so that it is considered in the differential diagnosis in a case of hemoptysis.

Nine human sparganosis cases in Thailand with molecular identification of causative parasite species.

Human sparganosis is one of the neglected diseases but important food-borne parasitic zoonoses. The disease is caused by larvae (spargana) of diphyllobothriidean tapeworm. Here, we describe nine cases of human sparganosis, caused by Spirometra erinaceieuropaei in a hospital in Thailand during 2001-2012. Clinical characteristics, treatment, and outcome of cases were revealed. Diagnosis and identification of causative parasite species was made by histopathological investigations followed by a polymerase chain reaction-based molecular method using formalin-fixed paraffin embedded tissues. The DNA samples were extracted from tissues and a partial fragment of cytochrome c oxidase subunit 1 (cox1) gene was amplified for the detection of parasitic DNA. Infection could be prevented by increasing activities on health communication by responsible public health agencies.

Levels of sparganum infections and phylogenetic analysis of the tapeworm Spirometra erinaceieuropaei sparganum in wild frogs from Henan Province in central China.

Sparganosis is a serious food-borne parasitic zoonosis caused by infection with Spirometra spargana. The prevalence of sparganum infection in wild frogs (Rana nigromaculata, R. limmochari, R. temporaria and Bufo gargarizans) was investigated in Henan Province of central China during 2008-2012. Of 3482 caught wild frogs, 565 (16.23%) were found to be infected with plerocercoids (spargana) of the genus Spirometra. Spargana were found in 14.85% (320/2155) of R. nigromaculata, 20.82% (233/1119) of R. limmochari and 10.91% (12/110) of R. temporaria frogs. However, no sparganum was found in B. gargarizans. To investigate the phylogenetic position of collected spargana, three mitochondrial DNA (mtDNA) regions, namely cytochrome c oxidase subunits 1 and 3 (cox1 and cox3), and NADH dehydrogenase subunit 4 (nad4), were amplified, sequenced and analysed. Sequences of cox1, cox3 and pnad4 were 417, 390 and 578 bp in length, respectively. The base composition of cox1, cox3 and pnad4 were generally AT rich with a mean of 63.5%, 68.3% and 67% AT, respectively. Phylogenetic analysis showed that all the sparganum isolates in Henan Province represented Spirometra erinaceieuropaei and were a well-supported clade. These findings demonstrated clearly the usefulness of the three mtDNA sequences for molecular identification and population genetics studies of S. erinaceieuropaei spargana of human and animal health significance.

Gastrointestinal parasites of free-living Indo-Pacific bottlenose dolphins (Tursiops aduncus) in the Northern Red Sea, Egypt

The present study represents the first report on the gastrointestinal parasite fauna infecting the free-living and alive Indo-Pacific bottlenose dolphins (Tursiops aduncus) inhabiting waters of the Red Sea at Hurghada, Egypt. A total of 94 individual faecal samples of the examined bottlenose dolphins were collected during several diving expeditions within their natural habitats. Using classical parasitological techniques, such as sodium acetate acetic acid formalin method, carbol fuchsin-stained faecal smears, coproantigen ELISA, PCR and macroscopical analyses, the study revealed infections with 21 different parasite species belonging to protozoans and metazoans with some of them bearing zoonotic and/or pathogenic potential. Four identified parasite species are potential zoonotic species (Giardia spp., Cryptosporidium spp., Diphyllobothrium spp., Ascaridida indet.); three of them are known to have high pathogenic potential for the examined dolphin species (Nasitrema attenuata, Zalophotrema spp. and Pholeter gastrophilus) and some appear to be directly associated with stranding events. In detail, the study indicates stages of ten protozoan species (Giardia spp., Sarcocystis spp., Isospora (like) spp., Cystoisospora (like) spp., Ciliata indet. I and II, Holotricha indet., Dinoflagellata indet., Hexamita (like) spp., Cryptosporidium spp.), seven trematode species (N. attenuata, Nasitrema spp. I and II, Zalophotrema curilensis, Zalophotrema spp., Pholeter gastrophilus, Trematoda indet.), one cestode species (Diphyllobothrium spp.), two nematode species (Ascaridida indet, Capillaria spp.) and one crustacean parasite (Cymothoidae indet.). Additionally, we molecularly identified adult worms of Anisakis typica in individual dolphin vomitus samples by molecular analyses. A. typica is a common parasite of various dolphin species of warmer temperate and tropical waters and has not been attributed as food-borne parasitic zoonoses so far. Overall, these parasitological findings include ten new host records for T. aduncus (i.e. in case of Giardia spp., Sarcocystis spp., Cryptosporidium spp., Nasitrema spp., Zalophotrema spp., Pholeter gastrophilus, A. typica, Capillaria spp., Diphyllobothrium spp. and Cymothoidae indet.). The present results may be used as a baseline for future monitoring studies targeting the impact of climate or other environmental changes on dolphin's health conditions and therefore contribute to the protection of these fascinating marine mammals.

Emerging Food-Borne Parasitic Zoonoses: A bird's eye view

Zoonotic transmission of parasitism is an underreported and under recognized, worldwide distributed entity. Humans acquire these infections either through food, water, soil or close contact with animals. Mostly parasitic zoonoses are those of neglected diseases but with more demand of the food supply, increased travelling and increased ratio of highly susceptible persons coupled with changes in culinary practices with simultaneous improvement in diagnostic tools as well as communication facilities. These conditions are emerging at an alarming rate. Global sourcing of food, coupled with changing consumer vogues, including the consumption of raw vegetables and undercooking to retain the natural taste and preserve heat-labile nutrients, can increase the risk of foodborne transmission. The increasing demand for raw or under-cooked food is also considered as one of the major reasons causing food borne infections, especially waterborne parasitic diseases, in the last decade. The present review will discuss the factor responsible for transmission and occurrence of zoonotic diseases along with different helminthes and protozoan parasites that

Parasites and food: ripe for exploitation

Parasites are often exploited for emotive or political purposes. This is especially so for a number of foodborne parasitic zoonoses, where this exploitation may not necessarily best serve the public good.

Paragonimus and Paragonimiasis in Vietnam: an Update

Paragonimiasis is a food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Vietnam, research on Paragonimus and paragonimiasis has been conducted in northern and central regions of the country. Using a combination of morphological and molecular methods, 7 Paragonimus species, namely P. heterotremus, P. westermani, P. skrjabini, P. vietnamensis, P. proliferus, P. bangkokenis and P. harinasutai, have been identified in Vietnam. Of these, the first 3, P. heterotremus, P. westermani and P. skrjabini, are known to infect humans in other countries. However, in Vietnam, only P. heterotremus, found in some northern provinces, has been shown to infect humans. Even nowadays, local people in some northern provinces, such as Lai Chau and Yen Bai, are still suffering from P. heterotremus infection. In some provinces of central Vietnam, the prevalence and infection intensity of P. westermani metacercariae in freshwater crabs (the second intermediate hosts) are extremely high, but human cases have not been reported. Likewise, although P. skrjabini was found in Thanh Hoa Province, its pathogenicity to humans in Vietnam still remains uncertain. The results of molecular phylogenetic analyses of Vietnamese Paragonimus species provides new insights on the phylogeny and taxonomy of the genus Paragonimus. Comprehensive molecular epidemiological and geobiological studies on the genus in Vietnam and adjacent countries are needed to clarify the biodiversity and public health significance of the lung flukes.

Molecular Variation in the Paragonimus heterotremus Complex in Thailand and Myanmar

Paragonimiasis is an important food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. Of the 7 members of the genus known in Thailand until recently, only P. heterotremus has been confirmed as causing human disease. An 8th species, P. pseudoheterotremus, has recently been proposed from Thailand, and has been found in humans. Molecular data place this species as a sister species to P. heterotremus, and it is likely that P. pseudoheterotremus is not specifically distinct from P. heterotremus. In this study, we collected metacercariae of both nominal species (identification based on metacercarial morphology) from freshwater crabs from Phetchabun Province in northern Thailand, Saraburi Province in central Thailand, and Surat Thani Province in southern Thailand. In addition, we purchased freshwater crabs imported from Myanmar at Myawaddy Province, western Thailand, close to the Myanmar-Thailand border. The DNAs extracted from excysted metacercariae were PCR-amplified and sequenced for ITS2 and cox1 genes. The ITS2 sequences were nearly identical among all samples (99-100%). Phylogenies inferred from all available partial cox1 sequences contained several clusters. Sequences from Indian P. heterotremus formed a sister group to sequences from P. pseudoheterotremus-type metacercariae. Sequences of P. heterotremus from Thailand, Vietnam, and China formed a separate distinct clade. One metacercaria from Phitsanulok Province was distinct from all others. There is clearly considerable genetic variation in the P. heterotremus complex in Thailand and the form referred to as P. pseudoheterotremus is widely distributed in Thailand and the Thai-Myanmar border region.

A review of foodborne bacterial and parasitic zoonoses in Vietnam.

Vietnam has experienced unprecedented economic and social development in recent years, and the livestock sector is undergoing significant transformations. Although food animal production is still dominated by small-scale ‘backyard’ enterprises with mixed crop–livestock or livestock–aquatic systems, there is a trend towards more intensive and vertically integrated operations. Changes in animal production, processing and distribution networks for meat and animal products, and the shift from wet markets to supermarkets will undoubtedly impact food safety risks in Vietnam in unforeseen and complex ways. Here, we review the available published literature on bacterial and parasitic foodborne zoonoses (FBZ) in Vietnam. We report on clinical disease burden and pathogen prevalence in animal reservoirs for a number of important FBZ, and outline opportunities for future research.

Protective Immunity against Trichinella spiralis Infection Induced by a Multi-Epitope Vaccine in a Murine Model

Trichinellosis is one of the most important food-borne parasitic zoonoses throughout the world. Because infected pigs are the major source of human infections, and China is becoming the largest international producer of pork, the development of a transmission-blocking vaccine to prevent swine from being infected is urgently needed for trichinellosis control in China. Our previous studies have demonstrated that specific Trichinella spiralis paramyosin (Ts-Pmy) and Ts-87 antigen could provide protective immunity against T. spiralis infection in immunized mice. Certain protective epitopes of Ts-Pmy and Ts-87 antigen have been identified. To identify more Ts-Pmy protective epitopes, a new monoclonal antibody, termed 8F12, was produced against the N-terminus of Ts-Pmy. This antibody elicited significant protective immunity in mice against T. spiralis infection by passive transfer and was subsequently used to screen a random phage display peptide library to identify recognized epitopes. Seven distinct positive phage clones were identified and their displayed peptides were sequenced. Synthesized epitope peptides conjugated to keyhole limpet hemocyanin were used to immunize mice, four of which exhibited larval reduction (from 18.7% to 26.3%, respectively) in vaccinated mice in comparison to the KLH control. To increase more effective protection, the epitope 8F7 that was found to induce the highest protection in this study was combined with two other previously identified epitopes (YX1 from Ts-Pmy and M7 from Ts-87) to formulate a multi-epitope vaccine. Mice immunized with this multi-epitope vaccine experienced a 35.0% reduction in muscle larvae burden after being challenged with T. spiralis larvae. This protection is significantly higher than that induced by individual-epitope peptides and is associated with high levels of subclasses IgG and IgG1. These results showed that a multi-epitope vaccine induced better protective immunity than an individual epitope and provided a feasible approach for developing a safer and more effective vaccine against trichinellosis.

Seroprevalence of anti-Toxoplasma gondii antibodies in cattle and pigs in Ibadan, Nigeria

Toxoplasmosis is an important food borne parasitic zoonoses. However, data on Toxoplasma gondii infection in domestic animals mostly used for human consumption in Nigeria are scarce. We thus conducted a survey on the seroprevalence of T. gondii infection in a representative sample of cattle and pigs in farms and the abattoirs between June and December 2012. Sera from 210 cattle (both sexes) and 302 pigs (both sexes), were examined for T. gondii specific IgG antibodies by indirect Enzyme linked immunosorbent assay (ELISA). The seroprevalences determined were 13.91% in cattle and 29.14% in pigs. The antibody levels ranged from 0.499 to 2.103 in cattle, and 0.544 to 3.020 in pigs. The prevalence of IgG anti-T. gondii antibodies was positively correlated with the age. The seroprevalences (26.23%) and (36.54%) for adult cattle and pigs respectively, were higher compared to younger groups. However the difference was not significant (P>0.05) in cattle but significant (P<0.05) in pigs. In Nigeria, exposure to raw or undercooked foods is a risk factor for T. gondii infection. Knowledge of the prevalence of toxoplasmosis will help to target prevention efforts.

Subcutaneous larva migrans of a sparganum in a gnathostomiasis-endemic area

We report a case of subcutaneous larva migrans caused by a tape worm (sparganum), a rare and under-recognized food-borne parasitic zoonosis, in Nan Province, Northern Thailand. An obese 56-year-old female presented a 3-month history of an intermittent migrating subcutaneous nodule in the abdomen associated with pain and itching. Physical examination showed a tubal resection scar on the lower abdomen with a swelling and movable irregular, and firm nodule with ill-defined border at the right lower quadrant of abdomen. Blood examination showed slight increased of eosinophil levels (6%). Excisional biopsy showed a viable non-segmented tape worm in the subcutaneous tissue identified by morphological examination and Western blot technique as a sparganum. Surgical removal is recommended for a worm in the subcutaneous connective tissues and superficial muscles.

Cutaneous gnathostomiasis: Report of 6 cases with emphasis on histopathological demonstration of the larva

Cutaneous gnathostomiasis is an emerging food-borne parasitic zoonosis. Histopathological demonstration of the larva on random biopsy specimen of erythematous plaques is infrequent because of its migrating nature. We sought to determine whether medical treatment with albendazole or ivermectin increases the diagnostic yield of skin biopsy specimen. A retrospective chart review was conducted in a private dermatology practice in Lima, Peru. Cases with a clinical diagnosis of nodular migratory panniculitis and pathological diagnosis of eosinophilic panniculitis or gnathostomiasis were reviewed. Only cases with definitive diagnosis confirmed by histopathology or parasite isolation were included in the study. A definitive diagnosis of gnathostomiasis was rendered in 6 of 55 reviewed cases. Histopathological or gross identification of the nematode's larva was made obtaining a biopsy specimen of papules or pseudofuruncles that developed after oral antiparasitic treatment. This is a retrospective case series study and no serologic testing was available. Biopsy of a papule or pseudofuruncle subsequent to oral treatment increases the likelihood of demonstrating the larva on skin biopsy specimen, which allows definitive diagnosis and may have therapeutic benefit.

Molecular Identification of a Case of Paragonimus pseudoheterotremus Infection in Thailand

Paragonimiasis is an important food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Southeast Asia, Paragonimus heterotremus is the only proven causative pathogen. Recently, a new Paragonimus species, P. pseudoheterotremus, was found in Thailand. This species is genetically similar to P. heterotremus and is considered as a sister species. However, infectivity or pathogenicity of P. pseudoheterotremus to humans remains unclear. We report the first confirmed human pulmonary paragonimiasis case caused by P. pseudoheterotremus infection. After polymerase chain reaction/sequencing of the DNA extracted from Paragonimus eggs in the sputum of the patient, partial internal transcribed spacer 2 and cytochrome c oxidase subunit 1 sequences were approximately identical (98-100%) with those of P. pseudoheterotremus. For P. heterotremus, the partial internal transcribed spacer 2 sequence was approximately identical (99-100%), but the partial mitochondrial cytochrome c oxidase subunit 1 sequence showed a similarity of 90-95%.

Human intestinal flukes Haplorchris taichui and Haplorchris pumilio in their intermediate hosts, freshwater snails of the families Thiaridae and Pachychilidae, in southern Thailand

The intestinal flukes Haplorchis taichui (Nishigori, 1924) and Haplorchis pumilio (Looss, 1899) (family Heterophyidae) are among the most important food-borne parasitic zoonoses found in Southeast Asia. Here, we report on a study of infection rates in freshwater snails of the two Cerithioidean families Thiaridae and Pachychilidae in the south of Thailand. The snails were collected by handpicking and scooping every two months for one year at several locations between January 2008 and September 2009. The snail samples were examined for parasitic infections in the lab by shedding and crushing methods. Parasite infections were found in snails from 13 of 34 sampling sites. Nine species of thiarid snails were collected in this study, viz. Melanoides tuberculatus (Muller, 1774) Melanoides jugicostis (Hanley & Theobald, 1876), Thiara scabra (Muller, 1774), Sermyla riqueti (Grateloup, 1840), Neoradina prasongi (Brandt, 1974) and Tarebia granifera (Lamarck, 1822) as well as in four species of pachychilids, viz. Brotia sp. 1, Brotia sp. 2, Brotia wykoffi and Adamietta housei (Lea, 1856). Among these only the three thiarid species (M. tuberculatus, M. jugicostis and N. prasongi) were found to be infected with the two parasites, while we found no record in pachychilids. The infection rates of H. taichui and H. pumilio were 0.59% (126/21,501) and 0.12% (25/21,501) respectively, with H. taichui found in the three thiarid species M. tuberculatus, M. jugicostis and N. prasongi. The infection rates were 0.96% (89/9,227), 0.11% (1/920) and 7.74% (36/465), respectively. H. pumilio was found in M. tuberculatus only, with an infection rate of 0.27% (25/9,227). (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

ELISA and some biochemical tests of heterophyidae infection in laboratory animals

Heterophyiasis is an important food-borne parasitic zoonosis in Egypt, among the inhabitants living around brackish-water lakes especially fishermen, and it is a common human parasite in the Nile Delta. The experiment was done on two laboratory animals (rats and dogs), and the time of sample collection was done periodically at 6, 9, 15, 21, and 28 days post-infection to evaluate different tests required. Whole blood was collected with heparin or ethylenediamine tetra-acetic acid as anticoagulant to help in the hematological studies such as red blood cells count (RBCs), white blood cells count, packed cell volume (PCV), and hemoglobin (Hb). Only marked increase in the total leuckocytic count was recorded while RBCs, PCV, and Hb were decreased in most of the results obtained. Total protein and globulin decreased while albumin and A/G ratio increased. Liver enzymes showing marked increase in aspartate aminotransferase and increase in alanine aminotransferase in dogs and rats denoting that liver has a role in the response to that infection. Kidney-function tests, urea, and creatinine showed slight increase at 6 days post-infection (d.p.i.). After preparation of different Ag (antigen) from different collected helminthes, the protein content of each was determined. The sera of infected animals were collected to find antibodies in their blood against the parasite using enzyme-linked immunosorbent assay and using crude heterophyid antigen collected from their intestines after scarification. The worms washed, homogenized, and then centrifuged to collect supernatant fluid as antigens. The results indicated that antibody starts to appear at 9 d.p.i. and increases till 21 and 28 d.p.i. and detection depends on antigen concentration.

Changing dietary habits in a changing world: Emerging drivers for the transmission of foodborne parasitic zoonoses

Changing eating habits, population growth and movements, global trade of foodstuff, changes in food production systems, climate change, increased awareness and better diagnostic tools are some of the main drivers affecting the emergence or re-emergence of many foodborne parasitic diseases in recent years. In particular, the increasing demand for exotic and raw food is one of the reasons why reports of foodborne infections, and especially waterborne parasitosis, have increased in the last years. Moreover increasing global demand for protein of animal origin has led to certain farming practices (e.g. aquaculture) increasing in emerging or developing countries, where health monitoring may not be sufficiently implemented. Therefore, high quality epidemiological data are needed which together with biological, economic, social and cultural variables should be taken into account when setting control programs for these increasingly popular production systems in emerging economies. This review focuses on the dietary, social, economic and environmental changes that may cause an increase in human exposure to foodborne parasites. Some examples illustrating these new epidemiological dynamics of transmission foodborne parasitic disease are presented.