Taenia Solium Taeniasis Research Articles

Taenia solium taeniasis and cysticercosis: extinction or outbreak

Taenia solium taeniasis and cysticercosis are neglected zoonotic diseases that affect human health and economies of developing countries. In this work, we formulate and analyze deterministic and continuous time Markov chain (CTMC) stochastic models to determine parameters that drive Taenia solium taeniasis and cysticercosis and the likelihood of their extinction. The basic reproduction number R_0 is computed by the next generation matrix approach, sensitivity index of each parameter in R_0 is derived by the normalized forward sensitivity index and the likelihood of diseases’ extinction is computed by the multitype branching process. The analysis shows that humans with Taenia solium taeniasis, infectious pork and Taenia solium eggs in the environment play an important role in the transmission of Taenia solium taeniasis and cysticercosis, and the model exhibits forward bifurcation at R_0=1. This implies that R_0<1 is a sufficient condition to eliminate Taenia solium taeniasis and cysticercosis. For CTMC model, analysis shows that the probability of Taenia solium taeniasis and cysticercosis extinction is high if the diseases emerge from humans with Taenia solium cysticercosis and there is an outbreak if the diseases emerge from either humans with Taenia solium taeniasis or infectious pork or Taenia solium eggs in the environment. To control Taenia solium taeniasis and cysticercosis, the intervention strategies should focus on improving hygiene and sanitation for reducing shedding rate of Taenia solium eggs in the environment, inspection of pork for reducing the rate of acquiring Taenia solium taeniasis and spraying of insecticides for killing Taenia solium eggs in the environment.

A Marked Decline in Taenia solium Taeniasis and Cysticercosis Infections in China: Possible Reasons from the Ecological Determinants Perspective

Taenia solium taeniasis/cysticercosis is an important global food-borne infectious disease transmitted between humans and pigs. According to both national surveys and field investigations, the prevalence of the disease in China has significantly decreased in recent decades. The primary disease control measures are health education and promotion, meat inspection, and chemotherapy. Other factors that influence or fundamentally affect human and pig T. solium taeniasis/cysticercosis have been identified, such as pig farming patterns shift and a revolution in sanitary toilets, which block T. solium transmission routes. Pig farming practices have shifted from backyard to large-scale intensive farming, thus decreasing pig contact with, and consumption of, human excreta. The increased in the use of sanitary toilets has facilitated hygiene by preventing of human excreta from contacting humans, or polluting the environment, feed, or water. The occurrence of human T. solium infections has markedly decreased as a result of these social changes. The objective of this review is to describe the ecological determinants of the cysticercosis decline in China.

How modelling can help steer the course set by the World Health Organization 2021-2030 roadmap on neglected tropical diseases.

The World Health Organization recently launched its 2021-2030 roadmap, Ending the Neglect to Attain the Sustainable Development Goals , an updated call to arms to end the suffering caused by neglected tropical diseases. Modelling and quantitative analyses played a significant role in forming these latest goals. In this collection, we discuss the insights, the resulting recommendations and identified challenges of public health modelling for 13 of the target diseases: Chagas disease, dengue, gambiense human African trypanosomiasis (gHAT), lymphatic filariasis (LF), onchocerciasis, rabies, scabies, schistosomiasis, soil-transmitted helminthiases (STH), Taenia solium taeniasis/ cysticercosis, trachoma, visceral leishmaniasis (VL) and yaws. This piece reflects the three cross-cutting themes identified across the collection, regarding the contribution that modelling can make to timelines, programme design, drug development and clinical trials.

Geographically Targeted Interventions versus Mass Drug Administration to Control Taenia solium Cysticercosis, Peru.

Optimal control strategies for Taenia solium taeniasis and cysticercosis have not been determined. We conducted a 2-year cluster randomized trial in Peru by assigning 23 villages to 1 of 3 geographically targeted intervention approaches. For ring screening (RS), participants living near pigs with cysticercosis were screened for taeniasis; identified cases were treated with niclosamide. In ring treatment (RT), participants living near pigs with cysticercosis received presumptive treatment with niclosamide. In mass treatment (MT), participants received niclosamide treatment every 6 months regardless of location. In each approach, half the villages received targeted or mass oxfendazole for pigs (6 total study arms). We noted significant reductions in seroincidence among pigs in all approaches (67.1% decrease in RS, 69.3% in RT, 64.7% in MT; p<0.001), despite a smaller proportion of population treated by targeted approaches (RS 1.4%, RT 19.3%, MT 88.5%). Our findings suggest multiple approaches can achieve rapid control of T. solium transmission.

How modelling can help steer the course set by the World Health Organization 2021-2030 roadmap on neglected tropical diseases

The World Health Organization recently launched its 2021-2030 roadmap, Ending the Neglect to Attain the Sustainable Development Goals, an updated call to arms to end the suffering caused by neglected tropical diseases. Modelling and quantitative analyses played a significant role in forming these latest goals. In this collection, we discuss the insights, the resulting recommendations and identified challenges of public health modelling for 13 of the target diseases: Chagas disease, dengue, gambiense human African trypanosomiasis (gHAT), lymphatic filariasis (LF), onchocerciasis, rabies, scabies, schistosomiasis, soil-transmitted helminthiases (STH), Taenia solium taeniasis/ cysticercosis, trachoma, visceral leishmaniasis (VL) and yaws. This piece reflects the three cross-cutting themes identified across the collection, regarding the contribution that modelling can make to timelines, programme design, drug development and clinical trials.

New insights on the Taenia solium tapeworm using molecular tools: age-based human definitive host prevalence and deliberation on parasite life span

ABSTRACT Information on age-based Taenia solium taeniasis prevalence is crucial for control of cysticercosis. T. solium taeniasis prevalence was determined for a village in Liangshan Prefecture, Sichuan Province, China that was co-endemic for T. solium, Taenia saginata asiatica, and Taenia saginata. Individuals who were Taenia egg-positive by stool microscopy and/or expelled tapeworms or proglottids post-treatment were diagnosed as having taeniasis. Infecting species was identified via multiplex PCR on tapeworm specimens or coproPCR followed by sequencing. In addition, initial stool samples from 10 children with taeniasis suspected of having spontaneous expulsion of tapeworms within the period between diagnosis and treatment were subject to species confirmation via coproPCR and sequencing. Of the 389 study subjects, 194 (49.9%) were diagnosed with taeniasis. Children (< 16 years of age) had a higher T. solium taeniasis prevalence (8.8%) than older individuals (2.5%) (P = 0.0127). Molecular analysis of initial stool samples from 7 of 10 children suspected of spontaneously passing tapeworms indicated 6 infections due to T. solium and 1 infection due to T. saginata. This study found that young children had a higher T. solium taeniasis prevalence than older individuals, providing additional support for the belief that adult T. solium likely has a relatively short lifespan compared to other Taenia species with human definitive hosts.

Status and control of common food-borne parasitic diseases in China: a review

Food-borne parasitic diseases include meat-borne, fish-borne, plant-borne, water-borne, mollusk-borne and freshwater crustacean-borne parasitic diseases. The review summarizes the current status and control of 6 major food-borne parasitic diseases in China, including clonorchiasus, paragonimiasis, Taenia solium taeniasis, toxoplasmosis, trichinellosis and angiostrongyliasis, aiming to increase the understanding of food-borne parasitic diseases and provide insights into the development of the control strategy for food-borne parasitic diseases. The transmission of food-borne parasitic diseases are predominantly associated with diet, and neither eating raw nor semi-cooked food is the most effective measure to prevent the development of food-borne parasitic diseases.

The viewpoint by White and colleagues critiquing the evaluation of the safety and efficacy of mass chemotherapy for Taenia solium taeniasis is unsubstantiated.

The viewpoint by White and colleagues critiquing the evaluation of the safety and efficacy of mass chemotherapy for Taenia solium taeniasis is unsubstantiated.

The data are inadequate to assess safety and efficacy of mass chemotherapy for Taenia solium taeniasis.

As members of the Pan American Health Organization (PAHO) and World Health Organization (WHO) guidelines development group on chemotherapy strategies for the control of Taenia solium taeniasis, we are very disappointed at the systematic review by Haby and colleagues. With respect to the analysis of efficacy, the authors did not account for differences in the methods used to ascertain the outcome in the studies analyzed. There are also major concerns regarding the safety analyses. Few of the included studies used carefully designed active surveillance protocols to detect epileptic seizures and/or chronic progressive headaches. These neurologic side effects, due the inadvertent killing of viable brain cysts, have been noted after mass therapy with praziquantel and albendazole. We wholeheartedly agree with the authors’ statement in their discussion that control programs applying chemotherapy using mass drug administration “need to be informed by evidence of the best drug and dose in terms of efficacy and side-effects.” Unfortunately, the flawed analysis that was published is contrary to that goal.

Hospitalization for Chagas disease, dengue, filariasis, leishmaniasis, schistosomiasis, strongyloidiasis, and Taenia solium taeniasis/cysticercosis, Italy, 2011-2016.

To analyze epidemiology and burden of Neglected Tropical Diseases (NTDs)in Italy. We used Hospital Discharge Records and number of residents in Italy to calculate number and rate of hospitalization for Chagas disease, dengue, filariasis, leishmaniasis, schistosomiasis, strongyloidiasis, Taenia solium taeniasis, and cysticercosis by sex, citizenship group, and region in the period 2011-2016. 7195 hospitalizations for NTDs were retrieved, accounting for 7375 diagnoses, 60% in Italians and 40% in foreigners. Male-to-female ratio was 2; the age group more commonly affected was 25-44years (32.5%). The most common diagnoses were leishmaniasis (34%), schistosomiasis (29%), strongyloidiasis (12%), Chagas disease (8%), and dengue (8%). Average yearly hospitalization rate per 100,000 residents for all NTDs was 2.05, 1.33, and 10.39 in general population, Italians, and foreign citizens, respectively. Hospitalization rates higher than 100 per 100,000 subjects were found in citizens from Sub-Saharan Africa (SSA) and Bolivia. NTDs have a not negligible burden in Italy. The most clinically relevant NTDs in Italy are leishmaniasis and schistosomiasis, followed by strongyloidiasis, Chagas disease, and dengue. Cystic echinococcosis, that was not included in the analysis since a similar study on this disease was recently published, should also be listed among the leading NTD in Italy. While schistosomiasis has its highest burden on population coming from highly endemic areas such as SSA, leishmaniasis is especially relevant in Italian-born residents of southern regions. Education at university and post-graduate levels, to increase the awareness of healthcare professionals on these topics, as well as targeted public health interventions (such as screening or presumptive treatment in high-risk groups), are an asset to improve clinical management and control of these diseases.

Systematic review of the effectiveness of selected drugs for preventive chemotherapy for Taenia solium taeniasis.

Preventive chemotherapy is a useful tool for the control of Taenia solium taeniasis and cysticercosis. The aim of this systematic review is to assess the scientific evidence concerning the effectiveness and safety of different drugs in preventive chemotherapy for T. solium taeniasis in endemic populations. A systematic review was conducted of controlled and uncontrolled studies, assessing the efficacy and adverse effects (among other outcomes) of albendazole, niclosamide and/or praziquantel for preventive chemotherapy of T. solium taeniasis. A comprehensive search was conducted for published and unpublished studies. Two reviewers screened articles, completed the data extraction and assessment of risk of bias. A meta-analysis of cure rate and relative reduction in prevalence was performed. The protocol for this review was registered on the International prospective register of systematic reviews (PROSPERO), number CRD42018112533. We identified 3555 records, of which we included 20 primary studies reported across 33 articles. Meta-analyses of drug and dose showed that a single dose of praziquantel 10mg/kg, albendazole 400mg per day for three consecutive days, or niclosamide 2g, resulted in better cure rates for T. solium taeniasis (99.5%, 96.4% and 84.3%, respectively) than praziquantel 5mg/kg or single dose albendazole 400mg (89.0% and 52.0%, respectively). These findings have a low certainty of evidence due to high risk of bias in individual studies and heterogeneity in combined estimates. In relation to side-effects, most studies reported either no or only mild and transient side-effects within the first three days following drug administration for all drugs and doses. Evidence indicated that praziquantel 10mg/kg, niclosamide 2g, and triple dose albendazole 400mg were effective as taenicides and could be considered for use in mass drug administration programs for the control of T. solium taeniasis. Evidence was not found that any of these drugs caused severe side effects at the indicated doses, although the extent of the available evidence was limited.

Taeniasis Solium dan Sistiserkosis pada Manusia

Taenia solium taeniasis (taeniasis) and cysticercosis in human are infectious diseases caused by pork tapeworm Taenia solium. They are zoonotic diseases and still a health problem in the world, especially in developing countries such as Indonesia. The prevalence of taeniasis and cysticercosis in Indonesia is still quite high at 2% - 48% with the highest prevalence in Papua. Human taeniasis can manifest as a asymptomatic or intestinal minimally symptomatic. Cysticercosis can involve of neural tissue (neurocysticercosis) may manifest epilepsy seizure, headache, neurological symptom, cognitive disabilities, and death. The habit of eating raw or undercooked pork, lack of sanitation, and a lack of supervision the slaughterhouse are some of the factors causing taeniasis and cysticercosis in human. Avoiding eating raw pork, cooking meat over temperature 54oC, supervision at slaughterhouses, and maintaining hygiene is a way to prevent taeniasis and cysticercosis, therefore it is necesarry to do more intensive programs to prevent and control the diseases.

Prevalence of Taenia Solium Taeniasis among Community Members of Kiambu County, Kenya

Taenia solium Taeniasis is an important zoonotic food borne intestinal parasitic disease causing abdominal pains, diarrhea and stunting in children. Humans get the infection on consumption of raw or under cooked infected pig meat with metacercode larvae or contaminated food and water. Adult worm is found in the intestines of humans, eggs are shed in feces constituting environmental contamination. Disease occurs worldwide but it is endemic where pigs are raised in free range system. A total of three hundred and eighty four stool samples were collected from 386 (163 males and 223 females) randomly selected adult members of the community members in Thika, Kiambu in 2016 for parasitological evaluation by microscopy for T. solium eggs. Each study participant signed an informed consent and provided one stool sample. Twenty six of the participants both males and females were found to be positive for T. solium eggs indicating an overall prevalence of 6.74%. Significant associations were observed in relation to latrine use (X2=43.406, p value =0.000), method of pork preparation (X2=10.271, p value=0.006), and frequency of deworming at (X218.275, p value=0.000). Taenia solium taeniasis is present in the community and in relatively high prevalence.

Taenia solium taeniasis and cysticercosis control and elimination through community-based interventions.

Taenia solium was declared potentially eradicable by the International Task Force for Disease Eradication in 1992. Yet, very few well-designed community-based randomized controlled trials have been conducted to measure the effectiveness of alternative control strategies. Most strategies have been tested in pre-post intervention designs in very few communities, often without a control group. The only two community-based randomized controlled trials suggest that an educational program alone or a combination of human and porcine mass treatment reduce porcine cysticercosis in the short term. A transmission dynamics model suggests that improved sanitation and pig management are more effective and sustainable than pig vaccination, human or porcine mass treatment. Current evidence does not support the eradication of Taenia solium in the foreseeable future. Investigators should follow international recommendations on the conduct of community-based randomized control trials to provide more valid estimates of the effect and cost-effectiveness of alternative control strategies for cysticercosis.

Neurocysticercosis is still prevalent in Mexico

In this work, we report the published cases of human and porcine cysticercosis, as well as Taenia solium taeniasis diagnosed in Mexico during the last 10 years. Numerical data allow us to state that this disease remains as a public health problem in our country. Whereas efficient tools have been developed for the diagnosis and prevention of cysticercosis, we strongly recommend further measures allowing the control and eventual eradication of this parasite in Mexico.

Chinchilla laniger can be used as an experimental model for Taenia solium taeniasis

Chinchilla laniger has been reported as an experimental definitive host for Taenia solium; however no information about its suitability and yield of gravid tapeworm proglottids containing viable and infective eggs has been published. In total 55 outbred female chinchillas were infected with 4 cysticerci each; hosts were immunodeppressed with 6 or 8 mg of methyl-prednisolone acetate every 14 days starting the day of infection and their discomfort was followed. Kinetics of coproantigen ELISA or expelled proglottids was used to define the infection status. Efficiency of tapeworm establishment was 21% and of parasite gravidity was 8%; chinchillas showed some degree of suffering along the infection. Viability of eggs obtained from gravid proglottids was tested comparing methods previously published, our results showed 62% viability with propidium iodide, 54% with trypan blue, 34% with neutral red, 30% by oncosphere activation and 7% with bromide 3-(4,5-dimetil-tiazol-2-il)-2,5-difenil-tetrazolio (MTT) reduction; no statistical differences were obtained between most techniques, except activation. Four piglets were infected with 50,000 eggs each, necropsy was performed 3 months later and, after counting the number of cysticerci recovered, the percentage of infection was similar to data obtained with T. solium eggs recovered from humans. Our results demonstrate that the experimental model of T. solium taeniasis in C. laniger is a good alternative for providing eggs and adult tapeworms to be used in different types of experiments; optimization of the model probably depends on the use of inbred hosts and on the reduction of infected animals' suffering.

Prevalence and associated risk factors of Taenia solium taeniasis in a rural pig farming community of north India

There is a lack of information on the disease burden due to Taenia solium taeniasis and its associated risk factors in pig farming communities throughout the world. The present study was conducted in a rural pig farming community of north India to estimate the prevalence of T. solium taeniasis and associated factors. Demographic, clinical and epidemiological data were collected from 1181 subjects in 210 households in 30 villages. Stool specimens from 924 subjects were examined for eggs of Taenia and other parasites. Identification of T. solium was confirmed by morphological features of segments and species-specific DNA detection from segments and stool. The prevalence of T. solium taeniasis was 18.6% (172/924); factors associated with taeniasis on multivariate analysis were age above 15 years, history of passage of Taenia segments in stool, undercooked pork consumption and poor hand hygiene (hand-washing with clay/water after defecation). Seventy-eight subjects (6.6%) with epilepsy were identified. The study showed alarmingly high rates of epilepsy and T. solium taeniasis in the study community; it highlights the need for large-scale imaging-based surveys to identify the factors associated with epilepsy including neurocysticercosis. Health education, mass anthelminthic therapy and other preventive measures are required to control the menace of the disease.

Taeniasis-cysticercosis in Southern Ecuador: assessment of infection status using multiple laboratory diagnostic tools

Taenia solium-taeniasis and cysticercosis were studied in the human and porcine populations of a rural community in the Southern Ecuadorian Andes. From the 1059 inhabitants, 800 serum samples and 958 stool samples could be collected. In addition, 646 from the estimated 1148 pigs were tongue inspected. Circulating antigen was detected by enzyme linked immunosorbent assay (Ag-ELISA) in 2.25% of the human population, whereas intestinal taeniasis was detected in 1.46% by the formalin-ether technique. Following treatment and recovery of tapeworm fragments these were all identified as T. solium. Porcine cysticercosis was diagnosed in 3.56% of the pigs by tongue inspection. In addition, enzyme linked immunoelectrotransfer blot (EITB) was performed on a subset group of 100 humans to confirm the results of the Ag-ELISA. One hundred serum samples from pigs were also analysed by EITB. It appeared that 43 and 74% of humans and pigs had antibodies against T. solium cysticerci, respectively. It is concluded that contrary to the high exposure of the human population to T. solium that is suggested by EITB, the number of active cysticercosis cases, diagnosed by Ag-ELISA, was low, which may indicate endemic stability. The further use of complementary diagnostic methods for a better understanding of the epidemiology of T. solium is suggested.

Epidemiology of Taenia solium taeniasis and cysticercosis in two rural Guatemalan communities.

Taenia solium taeniasis and cysticercosis are known to be endemic in Guatemala but no studies had been undertaken in rural communities where transmission was thought to occur. Two adjacent communities, Quesada and El Jocote, in the Department of Jutiapa were selected. The former had considerably better sanitary infrastructure than the latter. The seroprevalence of antibodies detected in humans by immunoblot to T. solium metacestode glycoprotein antigens was 10% and 17% and the prevalence of intestinal taeniasis was 1% and 2.8% in the two villages, respectively. Both of these represented statistically greater rates in El Jocote. Females were significantly more likely to be seropositive than males in the study as a whole. The majority of cases of intestinal taeniasis were due to T. solium. Cases of intestinal taeniasis were significantly more likely to be anti-cysticercus antibody-positive than the general population. Epilepsy was recorded in 2.8% and 2.9% of the populations of Quesada and El Jocote, respectively. Follow-up of this group and a group of asymptomatic individuals by computed tomography scan indicated that individuals with a history of seizures had a higher rate of abnormalities suggestive of neurocysticercosis. Cysts were present in the tongues of 4% of live pigs sampled in Quesada and 14% in El Jocote. In these two communities, which are probably representative of many others in Guatemala, T. solium appeared to be a significant public health problem.

Prevalence and risk factors for Taenia solium taeniasis and cysticercosis in humans and pigs in a village in Morelos, Mexico.

In a Mexican village in which Taenia solium infection was known to be endemic, we selected a cluster sample of 368 households (21% of the total) for demographic, environmental, and diagnostic surveys, and medical histories for taeniasis and cysticercosis. Coproparasitologic studies of 1,531 participants revealed infection by Taenia sp. in four (0.3%) individuals; however, 5.8% of the respondents reported a history of having passed tapeworm proglottids in feces. Of 1,552 human serum specimens, 10.8% tested positive in the cysticercosis immunoblot assay. Seropositivity increased with age and reached a maximum in subjects ages 46-55 years. Risk factors associated with seropositivity included a history of passing tapeworm proglottids, frequent consumption of pork, and poor personal and household hygiene (P less than 0.05). A history of seizures was also significantly associated with seropositivity (P less than 0.05); approximately one-third of persons with such histories were seropositive. Of 571 pigs examined by tongue inspection, 23 (4.0%) had cysticerci; infection rates increased with the age of pigs, and were higher in pigs that habitually ran loose or were fed human feces (P less than 0.05). Goodness of fit analysis confirmed that seropositive persons (but not infected pigs) were significantly clustered within households, particularly, in households in which a member reported a history of having passed tapeworm proglottids. The results of this study have identified community behavioral and environmental practices that must be modified to prevent continued transmission of cysticercosis and taeniasis.