Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 78
Filter
Add more filters

Publication year range
1.
Parasitology ; 150(10): 894-900, 2023 09.
Article in English | MEDLINE | ID: mdl-37621007

ABSTRACT

Four methods were compared for the diagnosis of human taeniasis caused by Taenia solium. Fecal samples from persons living in a T. solium endemic region of Madagascar were examined for taeniid eggs by the Kato­Katz method. Subsequently, samples positive (n = 16) and negative (n = 200) for T. solium eggs were examined by (i) amplification of the fragment of small subunit of the mitochondrial ribosomal RNA (rrnS) gene using conventional polymerase chain reaction (PCR) and (ii) a nested PCR of a fragment of the T. solium Tso31 gene. Additionally, 12 egg-positive and all egg-negative samples were tested for coproantigen detection. A further 9 egg-positive fecal samples were examined using both PCRs. Of the 12 egg-positive samples tested by PCRs and coproantigen methods, 9 (75%) were positive by rrnS PCR, 3 (25%) using Tso31-nested PCR and 9 (75%) by coproantigen testing. None of the 200 egg-negative fecal samples was positive in either rrnS or Tso31-nested PCR. Twenty of the 25 egg-positive samples (80%) were positive in rrnS PCR, and DNA sequencing of PCR amplicons was obtained from 18 samples, all confirmed to be T. solium. Twelve of the 25 egg-positive samples (48%) were positive in the Tso31-nested PCR, all of which were also positive by rrnS PCR. It is suggested that species-specific diagnosis of T. solium taeniasis may be achieved by either coprological examination to detect eggs or coproantigen testing, followed by rrnS PCR and DNA sequencing to confirm the tapeworm species in egg-positive or coproantigen-positive samples.


Subject(s)
Taenia solium , Taenia , Taeniasis , Humans , Animals , Taenia solium/genetics , Taeniasis/diagnosis , Taeniasis/epidemiology , Polymerase Chain Reaction , Feces , Species Specificity , Taenia/genetics
2.
Parasitology ; 150(9): 852-857, 2023 08.
Article in English | MEDLINE | ID: mdl-37496390

ABSTRACT

Neurocysticercosis is recognized as an important health issue in the Malagasy population. To date, investigations into prevalence of infection with the causative agent, Taenia solium, in the parasite's natural animal intermediate hosts, have relied on serological methods which have been found to be non-specific. We determined the prevalence of porcine cysticercosis among pigs from a contiguous area of the Betafo and Mandoto administrative districts, Vakinankaratra Region, Madagascar. One hundred and four slaughter-weight pigs were examined by detailed necropsy examination including slicing of the heart, tongue, masseter muscles, diaphragm and carcase musculature. Thirty-seven animals (35.6%) were found infected with T. solium, representing one of the highest rates of infection ever reported, worldwide. These findings highlight the importance of T. solium in Madagascar and support the need for increased efforts to prevent the parasite's transmission to reduce its burden on the health of the Malagasy population.


Subject(s)
Cysticercosis , Swine Diseases , Taenia solium , Swine , Animals , Madagascar/epidemiology , Prevalence , Swine Diseases/epidemiology , Cysticercosis/epidemiology , Cysticercosis/veterinary , Taenia solium/physiology
3.
Parasitology ; : 1-3, 2022 Oct 13.
Article in English | MEDLINE | ID: mdl-36226566

ABSTRACT

The EG95 recombinant vaccine is protective against cystic echinococcus in animal intermediate hosts. Preparation of the existing, registered EG95 vaccines involves semi-purification of the vaccine protein, adding to the cost of production. Truncation of the EG95 cDNA, shortening both the amino and carboxy-termini of the protein, leads to high levels of recombinant protein expression. The recombinant EG95 protein was prepared as a bacterin from clarified, whole bacterial lysate, and used in a vaccine trial in sheep against an experimental challenge infection with Echinococcus granulosus eggs. The EG95 bacterin was found to induce 98% protection. Use of this in a new generation EG95 vaccine would simplify production, facilitate new sources of the vaccine and potentially enhance uptake of vaccination in control of E. granulosus transmission.

4.
N Engl J Med ; 374(24): 2335-44, 2016 Jun 16.
Article in English | MEDLINE | ID: mdl-27305193

ABSTRACT

BACKGROUND: Taeniasis and cysticercosis are major causes of seizures and epilepsy. Infection by the causative parasite Taenia solium requires transmission between humans and pigs. The disease is considered to be eradicable, but data on attempts at regional elimination are lacking. We conducted a three-phase control program in Tumbes, Peru, to determine whether regional elimination would be feasible. METHODS: We systematically tested and compared elimination strategies to show the feasibility of interrupting the transmission of T. solium infection in a region of highly endemic disease in Peru. In phase 1, we assessed the effectiveness and feasibility of six intervention strategies that involved screening of humans and pigs, antiparasitic treatment, prevention education, and pig replacement in 42 villages. In phase 2, we compared mass treatment with mass screening (each either with or without vaccination of pigs) in 17 villages. In phase 3, we implemented the final strategy of mass treatment of humans along with the mass treatment and vaccination of pigs in the entire rural region of Tumbes (107 villages comprising 81,170 people and 55,638 pigs). The effect of the intervention was measured after phases 2 and 3 with the use of detailed necropsy to detect pigs with live, nondegenerated cysts capable of causing new infection. The necropsy sampling was weighted in that we preferentially included more samples from seropositive pigs than from seronegative pigs. RESULTS: Only two of the strategies implemented in phase 1 resulted in limited control over the transmission of T. solium infection, which highlighted the need to intensify the subsequent strategies. After the strategies in phase 2 were implemented, no cyst that was capable of further transmission of T. solium infection was found among 658 sampled pigs. One year later, without further intervention, 7 of 310 sampled pigs had live, nondegenerated cysts, but no infected pig was found in 11 of 17 villages, including all the villages in which mass antiparasitic treatment plus vaccination was implemented. After the final strategy was implemented in phase 3, a total of 3 of 342 pigs had live, nondegenerated cysts, but no infected pig was found in 105 of 107 villages. CONCLUSIONS: We showed that the transmission of T. solium infection was interrupted on a regional scale in a highly endemic region in Peru. (Funded by the Bill and Melinda Gates Foundation and others.).


Subject(s)
Cysticercosis/transmission , Disease Transmission, Infectious/prevention & control , Endemic Diseases/prevention & control , Taenia solium , Adolescent , Adult , Animals , Anthelmintics/therapeutic use , Cysticercosis/prevention & control , Cysticercosis/veterinary , Feasibility Studies , Female , Health Education , Humans , Male , Mass Screening , Middle Aged , Peru , Sus scrofa/parasitology , Taenia solium/isolation & purification , Taeniasis/prevention & control , Taeniasis/transmission , Vaccines , Young Adult
5.
Parasitology ; 145(6): 807-813, 2018 05.
Article in English | MEDLINE | ID: mdl-29173204

ABSTRACT

Echinococcus granulosus is an important zoonotic parasite that is distributed worldwide. The EG95 vaccine was developed to assist with control of E. granulosus transmission through the parasite's livestock intermediate hosts. The vaccine is based on a recombinant antigen encoded by a gene which is a member of a multi-gene family. With the recent availability of two E. granulosus draft genomes, we sought to map the eg95 gene family to the genomes. We were unable to map unequivocally any of the eg95 gene family members which had previously been characterized by cloning and sequencing both strands of genomic DNA fragments. Our inability to map EG95-related genes to the genomes has revealed limitations in the assembled sequence data when utilized for gene family analyses. This study contrasts with the expectations expressed in often high-profile publications describing draft genomes of parasitic organisms, highlighting deficiencies in currently available genomic resources for E. granulosus and provides a cautionary note for research which seeks to utilize these genome datasets.


Subject(s)
Antigens, Helminth/immunology , Echinococcus granulosus/genetics , Genome, Helminth , Helminth Proteins/genetics , Animals , Antigens, Helminth/genetics , Cloning, Molecular , DNA, Complementary , Echinococcosis/immunology , Echinococcosis/parasitology , Echinococcosis/prevention & control , Echinococcus granulosus/immunology , Helminth Proteins/immunology , Humans , Vaccines/genetics , Vaccines/immunology
6.
Parasitology ; 143(4): 416-20, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26892239

ABSTRACT

Specific antibody responses were assessed in pigs immunized with the Taenia solium vaccine TSOL18. Anti-TSOL18 responses were compared 2 weeks after secondary immunization, where the interval between primary and secondary immunization was 4, 8, 12, 16 or 20 weeks. All animals responded to the vaccine and there was no diminution in antibody responses in animals receiving their second injection after an interval up to 20 weeks. Pigs receiving vaccinations at an interval of 12 weeks developed significantly increased antibody responses compared with animals receiving immunizations 4 weeks apart (P = 0.046). The ability to deliver TSOL18 vaccination effectively where the revaccination schedule can be delayed for up to 12-16 weeks in pigs increases the options available for designing T. solium control interventions that incorporate TSOL18 vaccination.


Subject(s)
Antibodies, Helminth/blood , Immunization, Secondary/veterinary , Swine Diseases/prevention & control , Taenia solium/immunology , Taeniasis/veterinary , Vaccines/immunology , Animals , Antibodies, Helminth/biosynthesis , Female , Immunization Schedule , Immunization, Secondary/standards , Immunoglobulin G/biosynthesis , Immunoglobulin G/blood , Injections, Intramuscular/veterinary , Male , Swine , Swine Diseases/immunology , Taeniasis/immunology , Taeniasis/prevention & control , Time Factors , Vaccines/administration & dosage
7.
Immunol Rev ; 239(1): 237-70, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21198676

ABSTRACT

The neglected tropical diseases (NTDs) represent a group of parasitic and related infectious diseases such as amebiasis, Chagas disease, cysticercosis, echinococcosis, hookworm, leishmaniasis, and schistosomiasis. Together, these conditions are considered the most common infections in low- and middle-income countries, where they produce a level of global disability and human suffering equivalent to better known conditions such as human immunodeficiency virus/acquired immunodeficiency syndrome and malaria. Despite their global public health importance, progress on developing vaccines for NTD pathogens has lagged because of some key technical hurdles and the fact that these infections occur almost exclusively in the world's poorest people living below the World Bank poverty line. In the absence of financial incentives for new products, the multinational pharmaceutical companies have not embarked on substantive research and development programs for the neglected tropical disease vaccines. Here, we review the current status of scientific and technical progress in the development of new neglected tropical disease vaccines, highlighting the successes that have been achieved (cysticercosis and echinococcosis) and identifying the challenges and opportunities for development of new vaccines for NTDs. Also highlighted are the contributions being made by non-profit product development partnerships that are working to overcome some of the economic challenges in vaccine manufacture, clinical testing, and global access.


Subject(s)
Neglected Diseases/immunology , Parasitic Diseases/immunology , Parasitic Diseases/prevention & control , Protozoan Vaccines , Vaccines , Animals , Disease Models, Animal , Helminthiasis/immunology , Helminthiasis/prevention & control , Helminthiasis/therapy , Humans , Intestinal Diseases, Parasitic/immunology , Intestinal Diseases, Parasitic/prevention & control , Intestinal Diseases, Parasitic/therapy , Neglected Diseases/epidemiology , Neglected Diseases/prevention & control , Neglected Diseases/therapy , Parasitic Diseases/epidemiology , Parasitic Diseases/therapy , Poverty Areas , Protozoan Infections/immunology , Protozoan Infections/prevention & control , Protozoan Infections/therapy , Protozoan Vaccines/immunology , Tropical Medicine , Vaccines/immunology
8.
Parasitology ; 140(13): 1566-77, 2013 Nov.
Article in English | MEDLINE | ID: mdl-23947762

ABSTRACT

Neurocysticercosis continues to be a major health burden on humans living in many regions of the world, despite the availability of highly effective taeniacides and identification of the cause, Taenia solium, as being potentially eradicable. Several T. solium control trials have been undertaken, generally achieving limited success and none that has been fully documented has achieved what was demonstrated to be a sustainable level of disease control. Pigs act as intermediate hosts for T. solium and two new control tools have become available for application in pigs - single-dose oxfendazole treatment of porcine cysticercosis and the TSOL18 vaccine. Three potential intervention scenarios for pigs are compared for control of cysticercosis, using either oxfendazole or vaccination. A control scenario involving vaccination plus oxfendazole treatment delivered at 4 monthly intervals was predicted to achieve the best outcome, with no pigs slaughtered at 12 months of age having viable T. solium cysticerci. Now that new control tools are available, there are opportunities to concentrate research attention on evaluation of novel control scenarios leading to the implementation of effective and sustainable control programmes and a reduction in the global burden of neurocysticercosis.


Subject(s)
Communicable Disease Control/methods , Neurocysticercosis/prevention & control , Neurocysticercosis/veterinary , Swine Diseases/prevention & control , Vaccination , Vaccines/administration & dosage , Animals , Anthelmintics/therapeutic use , Antigens, Helminth/immunology , Benzimidazoles/therapeutic use , Clinical Trials as Topic , Communicable Disease Control/organization & administration , Humans , Neurocysticercosis/drug therapy , Neurocysticercosis/immunology , Swine , Swine Diseases/drug therapy , Swine Diseases/immunology , Swine Diseases/transmission , Taenia solium/drug effects , Taenia solium/immunology , Vaccines/immunology
9.
Commun Biol ; 5(1): 199, 2022 03 03.
Article in English | MEDLINE | ID: mdl-35241789

ABSTRACT

Cystic echinococcosis is a socioeconomically important parasitic disease caused by the larval stage of the canid tapeworm Echinococcus granulosus, afflicting millions of humans and animals worldwide. The development of a vaccine (called EG95) has been the most notable translational advance in the fight against this disease in animals. However, almost nothing is known about the genomic organisation/location of the family of genes encoding EG95 and related molecules, the extent of their conservation or their functions. The lack of a complete reference genome for E. granulosus genotype G1 has been a major obstacle to addressing these areas. Here, we assembled a chromosomal-scale genome for this genotype by scaffolding to a high quality genome for the congener E. multilocularis, localised Eg95 gene family members in this genome, and evaluated the conservation of the EG95 vaccine molecule. These results have marked implications for future explorations of aspects such as developmentally-regulated gene transcription/expression (using replicate samples) for all E. granulosus stages; structural and functional roles of non-coding genome regions; molecular 'cross-talk' between oncosphere and the immune system; and defining the precise function(s) of EG95. Applied aspects should include developing improved tools for the diagnosis and chemotherapy of cystic echinococcosis of humans.


Subject(s)
Echinococcosis , Echinococcus granulosus , Vaccines , Animals , Antigens, Helminth/genetics , Chromosomes , Echinococcosis/genetics , Echinococcosis/prevention & control , Echinococcus granulosus/genetics , Genotype , Helminth Proteins/genetics , Vaccines/genetics
10.
J Immunol Methods ; 497: 113121, 2021 10.
Article in English | MEDLINE | ID: mdl-34352238

ABSTRACT

Taenia solium oncosphere protein TSOL18 is the host-protective antigen against porcine cysticercosis. Little attention has been given to use it as target molecule in immunodiagnostic tests. The objective of this paper is to describe the immunodiagnostic potential of monoclonal antibodies (MoAbs) raised against conformational epitopes of TSOL18. Three murine IgG1 MoAbs (25D12C1, 21C2D2, 10H1F2) against three different conformational epitopes of TSOL18 were produced and evaluated with an inhibition enzyme-linked immunosorbent assay (i-ELISA) for the detection of anti-TSOL18 and anti-oncosphere antibodies. Serum samples from pigs immunized with TSOL18 inhibited the binding of the three MoAbs to TSOL18 antigen in i-ELISA. The highest inhibition of anti-TSOL18 antibodies in immunized pigs was observed with MoAb 25D12C1. Ten field sera (12.19%) from 82 non-vaccinated and non-infected pigs showed anti-oncosphere antibodies inhibiting the binding of MoAb 25D12C1. Anti-oncosphere antibodies in pigs experimentally infected with T. solium eggs inhibited the binding of MoAb 25D12C1 from 2 to 8 week-post infection. It is concluded that MoAb 25D12C1 has excellent immunodiagnostic potentials to detect anti-oncosphere antibodies in the intermediate hosts at early exposure to T. solium eggs. Further investigations on potential use of MoAb 25D12C1 in a capture antigen ELISA for the detection of post-oncospheral antigens in infected pigs cannot be overemphasized.


Subject(s)
Antibodies, Helminth/blood , Antibodies, Monoclonal/immunology , Antigens, Helminth/immunology , Enzyme-Linked Immunosorbent Assay , Immunoglobulin G/immunology , Taenia solium/immunology , Taeniasis/diagnosis , Animals , Antibody Specificity , Biomarkers/blood , Disease Models, Animal , Epitopes , Predictive Value of Tests , Sus scrofa , Taeniasis/immunology , Taeniasis/parasitology
11.
Int J Parasitol ; 51(13-14): 1167-1192, 2021 12.
Article in English | MEDLINE | ID: mdl-34757089

ABSTRACT

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.


Subject(s)
Cestoda , Cestode Infections , Echinococcosis , Echinococcus granulosus , Neurocysticercosis , Parasites , Animals , Cestode Infections/diagnosis , Cestode Infections/drug therapy , Cestode Infections/epidemiology , Dogs , Echinococcosis/parasitology
12.
Infect Dis Poverty ; 10(1): 34, 2021 Mar 20.
Article in English | MEDLINE | ID: mdl-33743828

ABSTRACT

BACKGROUND: Neurocysticercosis caused by Taenia solium when the parasite lodges in the central nervous system, is an important cause of human seizures and mortality in sub-Saharan Africa. The parasite is prevalent in many regions of Uganda. Pigs are intermediate hosts for T. solium, and we evaluated a T. solium control program in pigs, involving vaccination of pigs with the TSOL18 vaccine and treatment with oxfendazole. METHODS: The study was conducted in two districts of Eastern Uganda involving the rural village communities of Bukedea (intervention area) and Kumi (control area) during 2016-2017. Seven hundred and thirty-four households were enrolled in the study. Pigs in the intervention area received intramuscular immunizations with TSOL18 (Cysvax™) and an oral medication with 30 mg/kg oxfendazole (Paranthic™) at approximately 3-monthly intervals for 18 months. Porcine cysticercosis was evaluated by post-mortem examination. At the beginning of the study, 111 pigs were examined. In an interim evaluation in the intervention area, 55 pigs were evaluated 12 months after starting the project. At the end of the study approximately 3 months after the final intervention, 55 pigs from the intervention area and 56 pigs from the control area were evaluated. RESULTS: The prevalence of porcine cysticercosis for the two sites was 16.2% at the beginning of the study (17.2% in the intervention area and 15.1% in the control area) with no statistically significant difference (P = 0.759) between the two study sites. Among the 110 animals assessed from the intervention site (55 at the interim evaluation and 55 at the final evaluation), no pig with viable T. solium cysts was found. There was a statistically significant difference between the prevalence at baseline (17.2%) and at the end of the study (0%) in the intervention area (P = 0.001) and a statistically significant difference between the intervention (0%) and control areas (5.4%) (P = 0.041) at the end of the study. CONCLUSIONS: Three-monthly concurrent vaccination of pigs with the TSOL18 vaccine and medication with oxfendazole eliminated T. solium transmission by the animals involved in the study. Application of vaccination with medication in pigs has the potential to reduce transmission of T. solium in Uganda and other endemic countries.


Subject(s)
Anthelmintics/therapeutic use , Benzimidazoles/therapeutic use , Cysticercosis/veterinary , Swine Diseases/drug therapy , Swine Diseases/prevention & control , Animals , Antigens, Helminth , Cysticercosis/drug therapy , Cysticercosis/epidemiology , Cysticercosis/prevention & control , Humans , Swine , Swine Diseases/epidemiology , Taenia solium/drug effects , Uganda/epidemiology , Vaccines
13.
PLoS Negl Trop Dis ; 15(3): e0009253, 2021 03.
Article in English | MEDLINE | ID: mdl-33684115

ABSTRACT

BACKGROUND: Cystic echinococcosis (CE) is an important cause of human morbidity and mortality worldwide, particularly in Morocco and other North African countries. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the potential of three strategies to reduce Echinococcus granulosus transmission: (1) 4-monthly treatment of dogs with praziquantel, (2) vaccination of sheep with the EG95 vaccine and (3) a combination of both measures. These measures were implemented during four consecutive years in different areas of the Middle Atlas Mountains in Morocco. The outcome of the interventions was assessed through hydatid cyst (viable and non-viable) counts in liver and lungs using necropsy or in vivo ultrasound examination of the liver. A total of 402 lambs were recruited for annual vaccination with the EG95 anti-E. granulosus vaccine and 395 similar lambs were selected as non-vaccinated controls. At approximately four years of age the relative risk (estimated as odds ratio) for vaccinated sheep to have viable hydatid cysts compared with non-vaccinated controls was 3% (9.37% of the vaccinated sheep were found infected while 72.82% of the controls were infected; p = 0.002). The number of viable cysts in vaccinated animals was reduced by approximately 97% (mean counts were 0.28 and 9.18 respectively; p<0.001). An average of 595 owned dogs received 4-monthly treatment during the 44 months trial, corresponding to 91% of the owned dog population. Approximately, 5% of them were examined for E. granulosus adult worms by arecoline purge or eggs in feces (confirmed by PCR). The proportion of infected dogs significantly decreased after treatment (12% versus 35%; p<0.001). Post-treatment incidence of re-infestation corresponded to a monthly risk of 4% (95% CI: 3-6%). Treatment of owned dogs on a 4-monthly basis did not reduce the level of transmission of E. granulosus to sheep, nor did it enhance the level of control generated by vaccination of sheep with EG95, possibly because of unowned dogs and wild canids were not treated. CONCLUSIONS/SIGNIFICANCE: These data suggest that vaccination of sheep with EG95 has the potential to reduce the level of CE in Morocco and in other parts of the world with similar transmission dynamics. Under the epidemiological circumstances existing in the trial area, 4-monthly treatment of owned dogs with praziquantel was insufficient to have a major impact of E. granulosus transmission to sheep.


Subject(s)
Antigens, Helminth/immunology , Dog Diseases/drug therapy , Echinococcosis/prevention & control , Echinococcosis/veterinary , Helminth Proteins/immunology , Praziquantel/therapeutic use , Sheep Diseases/prevention & control , Vaccination/veterinary , Animals , Dogs , Morocco/epidemiology , Sheep , Sheep Diseases/diagnostic imaging , Sheep Diseases/pathology
14.
Infect Immun ; 78(10): 4363-73, 2010 Oct.
Article in English | MEDLINE | ID: mdl-20643854

ABSTRACT

Taenia ovis is a cestode parasite infecting primarily sheep as intermediate hosts and dogs as definitive hosts. The first highly effective, recombinant vaccine against a parasitic organism was developed against T. ovis infection in sheep. Three separate host-protective antigens (To16, To18, and To45W) have been cloned from the oncosphere of the parasite. We localize these antigens in the oncosphere by using quantitative immunogold labeling and transmission electron microscopy. The three antigens were uniquely associated with penetration gland cells. The cytoplasm and secretory granules of both penetration gland type 1 and type 2 cells exhibited statistically significant levels of staining for each of the three antigens. The intensity of labeling of the penetration gland type 1 cell was approximately three to five times greater (P < 0.01) compared to the level of staining intensity seen in the penetration gland type 2 cell. In activated oncospheres, secretory blebs were found to contain granules with a structure similar to those observed in the penetration gland cells. The granules within the secretory blebs were shown to stain specifically for the presence of each of the three host-protective antigens. The absence of surface location of the T. ovis antigens suggests that the parasite may not be susceptible to vaccine-induced antibody- and complement-mediated attack until some postoncospheral development has occurred after infection of the intermediate host.


Subject(s)
Antigens, Helminth/immunology , Taenia/immunology , Taeniasis/prevention & control , Vaccines , Animals , Immunohistochemistry , Mice , Mice, Inbred BALB C , Microscopy, Electron, Transmission , Sensitivity and Specificity , Taenia/ultrastructure , Vaccines/immunology
15.
Trends Parasitol ; 36(7): 575-578, 2020 07.
Article in English | MEDLINE | ID: mdl-32376114

ABSTRACT

Changes in the incidence of porcine cysticercosis is used commonly in the assessment of efforts to control the transmission of Taenia solium, the cause of human neurocysticercosis. Although cysticerci may occasionally occur in tissues other than the striated muscles, particularly the brain, infection in pigs can be diagnosed reliably by assessment of muscle tissue alone.


Subject(s)
Cysticercosis/veterinary , Muscle, Skeletal/parasitology , Swine Diseases/diagnosis , Taenia solium , Animals , Cysticercosis/diagnosis , Cysticercosis/transmission , Humans , Neurocysticercosis/parasitology , Neurocysticercosis/prevention & control , Neurocysticercosis/transmission , Swine , Swine Diseases/parasitology , Swine Diseases/transmission
16.
Acta Trop ; 205: 105378, 2020 May.
Article in English | MEDLINE | ID: mdl-32057776

ABSTRACT

In the 1930's Kozen Yoshino published 6 papers on Taenia solium. One of these papers is particularly important because it describes the outcomes of experimental infections with T. solium tapeworms in four volunteers, Yoshino being one of them. The paper was written in an old form of the Japanese language, making it almost inaccessible to most researchers around the world. Here we provide a non-literal translation of this work and some brief comments by the translators. Each of the four volunteers swallowed three or five cysticerci recovered from an experimentally infected pig. Each person was found to have harbored 2 - 5 tapeworms when the infections were terminated by drug treatment between 120 and 451 days after infection. The pre-patent period recorded by Yoshino's volunteers was between 62 and 72 days based on the first appearance of gravid proglottids (GPs) in the feces. In one subject, the number of GPs appearing in each bowel movement was tracked daily for 371 days following the first appearance of GPs in the feces, together with the number of bowel movements each day. GPs were observed on 275 of the 284 days on which the subject defecated during which observations were made. There was a decline in the number of GPs over the observation period; proglottids were observed on 97% of all days on which defecation occurred, they were present on 87% of days in the last month of infection. The cumulative number of GPs for a month in the 1st, 6th and 12th months of patent infection was 334, 174 and 126, respectively.


Subject(s)
Feces/parasitology , Taenia solium/isolation & purification , Taeniasis/parasitology , Animals , History, 19th Century , History, 20th Century , Humans , Japan , Swine
17.
Acta Trop ; 201: 105203, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31574252

ABSTRACT

Detailed post mortem analyses of 68 free-ranging, slaughter-age pigs from two sites in the Banke District of Nepal identified 36% as being infected with Echinococcus granulosus. The cysts ranged from infertile, immature cysts a few millimetres in diameter to fertile cysts >10 cm in diameter. PCR RFLP and DNA sequencing identified the cysts as being E. granulosus sensu stricto. The Banke district has recently been identified as having a high prevalence of porcine cysticercosis. These data suggest that cestode zoonoses in this, and possibly other parts of Nepal may be a serious concern for human health. An assessment of the level of human cystic echinococcosis and neurocysticercosis, in the region is warranted and the introduction of control measures are required to limit the parasites' transmission.


Subject(s)
Echinococcosis/veterinary , Swine Diseases/epidemiology , Animals , Echinococcosis/epidemiology , Echinococcus granulosus/genetics , Female , Humans , Male , Nepal/epidemiology , Swine , Zoonoses/epidemiology
18.
Parasit Vectors ; 13(1): 534, 2020 Oct 27.
Article in English | MEDLINE | ID: mdl-33109255

ABSTRACT

BACKGROUND: Taenia solium is a zoonotic parasite responsible for neurocysticercosis-a major cause of late-onset acquired epilepsy in humans. Lack of affordable, specific and sensitive diagnostic tools hampers control of the parasite. This study assessed the performance of an antigen detection enzyme-linked immunosorbent assay (Ag-ELISA) in the diagnosis of viable T. solium cysticercosis in naturally infected slaughter-age pigs in an endemic area in Tanzania. METHODS: A total of 350 pigs were bled before they were slaughtered and their carcases examined. Serum was analyzed for circulating antigens by using a monoclonal antibody-based B158/B60 Ag-ELISA. Each carcase was examined for the presence of Taenia hydatigena cysticerci and half carcase musculature together with the whole brain, head muscles, tongue, heart and diaphragm were sliced with fine cuts (< 0.5 cm) to reveal and enumerate T. solium cysticerci. Half carcase dissection can detect at least 84% of infected pigs. Prevalence and their 95% confidence intervals (CI) were calculated in Stata 12. Sensitivity, specificity, predictive values and likelihood ratios were determined. RESULTS: Twenty-nine pigs (8.3%, 95% CI: 5.6-11.7%) had viable T. solium cysticerci while 11 pigs had T. hydatigena cysticerci (3.1%, 95% CI: 1.6-5.5%). No co-infection was observed. Sixty-eight pigs (19.4%, 95% CI: 15.4-20%) tested positive on Ag-ELISA; of these, 24 had T. solium cysticerci and 7 had T. hydatigena cysticerci. Sensitivity and specificity were determined to be 82.7% and 86.3%, respectively. Positive and negative predictive values were 35.2% and 98.2%, respectively. Likelihood ratios for positive and negative Ag-ELISA test results were 6.0 and 0.2, respectively. There was a significant positive correlation between the titre of circulating antigens and intensity of T. solium cysticerci (r(348) = 0.63, P < 0.001). CONCLUSIONS: The Ag-ELISA test characteristics reported in this study indicate that the test is more reliable in ruling out T. solium cysticercosis in pigs, than in confirming it. Hence, a negative result will almost certainly indicate that a pig has no infection, but a positive result should always be interpreted with caution. Estimates of T. solium prevalence based on Ag-ELISA results should, therefore, be adjusted for test performance characteristics and occurrence of T. hydatigena.


Subject(s)
Cysticercosis/veterinary , Enzyme-Linked Immunosorbent Assay/veterinary , Swine/parasitology , Taenia solium/immunology , Animals , Antibodies, Helminth/blood , Cysticercosis/diagnosis , Cysticercosis/transmission , Enzyme-Linked Immunosorbent Assay/methods , Neurocysticercosis/transmission , Neurocysticercosis/veterinary , Serologic Tests/methods , Serologic Tests/veterinary , Swine Diseases/diagnosis , Swine Diseases/parasitology , Taenia solium/isolation & purification , Tanzania/epidemiology , Zoonoses/diagnosis , Zoonoses/parasitology
19.
Zoonoses Public Health ; 66(8): 889-899, 2019 12.
Article in English | MEDLINE | ID: mdl-31529690

ABSTRACT

Cystic echinococcosis (CE), caused by Echinococcus granulosus, is a chronic and debilitating zoonotic larval cestode infection in humans, which is principally transmitted between dogs and domestic livestock, particularly sheep. Human CE occurs in almost all pastoral communities and rangeland areas of the underdeveloped and developed world. Control programmes against CE have been implemented in several endemic countries to reduce or eliminate the disease. New Zealand and Tasmania are examples of some of the first programmes to be undertaken (in insular territories) and which were very successful in the elimination of CE. The advent and proven effectiveness of praziquantel, plus the experience of insular models, produced high expectations for rapid advances in a second generation of control programmes undertaken in continental areas (Argentina, Uruguay and Chile). Nevertheless, only moderate gains in CE control have been made and the impact on prevalence among humans has been slight. A major impediment to the adoption of procedures that were successful in New Zealand and Tasmania has been the requirement to administer praziquantel to dogs in rural areas eight times per year over numerous years. In addition, there have been clear technological improvements made in the diagnosis of canine echinococcosis for surveillance, the genetic characterization of parasite strains and in vaccination against CE infection in livestock. In order to establish new paradigms and appropriate combinations of control strategies, we have carried out a review and discussion of the available control tools and control models. Control strategies must be suitable and sustainable to benefit the Echinococcosis-endemic areas primarily, which at the same time are the poorest regions of the world.


Subject(s)
Echinococcosis/prevention & control , Echinococcus granulosus/pathogenicity , Livestock/parasitology , Animals , Anthelmintics/therapeutic use , Argentina/epidemiology , Chile/epidemiology , Dog Diseases/parasitology , Dogs , Echinococcosis/epidemiology , Echinococcosis/transmission , Humans , Praziquantel/therapeutic use , Prevalence , Sheep , Sheep Diseases/parasitology , Uruguay/epidemiology , Zoonoses
20.
Trends Parasitol ; 35(8): 592-595, 2019 08.
Article in English | MEDLINE | ID: mdl-31151880

ABSTRACT

The cystiSim model was used to compare strategies for the control of Taenia solium. A three-monthly intervention in pigs for 3 years was substantially more effective than biannual treatment for taeniasis in the human population for 5 years. The intervention period could be shortened further by combining pig and human interventions.


Subject(s)
Models, Theoretical , Neurocysticercosis/prevention & control , Swine Diseases/prevention & control , Taeniasis/prevention & control , Zoonoses/prevention & control , Animals , Humans , Swine , Swine Diseases/drug therapy , Taenia solium/physiology , Taeniasis/transmission
SELECTION OF CITATIONS
SEARCH DETAIL