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Postgraduate Medical Journal Jun 1998Neurocysticercosis is the most common parasitic disease of the central nervous system. Varied clinical manifestations occur, due to deposition of larvae of the parasite... (Review)
Review
Neurocysticercosis is the most common parasitic disease of the central nervous system. Varied clinical manifestations occur, due to deposition of larvae of the parasite Taenia solium in cerebral parenchyma, meninges, spinal cord, muscles, eyes and skin. The diagnosis of neurocysticercosis can be made with a fairly high degree of accuracy with the help of computed tomography and magnetic resonance imaging. Serological tests and histopathological examination of subcutaneous nodules provide additional support in establishing the diagnosis. The anticysticercal drugs albendazole and praziquantel have been extensively used, and found to be effective for all types of neurocysticercosis. However, recently controversy has been raised about their safety, and long-term clinical usefulness. Preventive health measures, such as provision of safe drinking water and excretion disposal, still offer the best ways to manage this disease.
Topics: Animals; Humans; Magnetic Resonance Imaging; Neurocysticercosis; Prognosis; Taenia; Tomography, X-Ray Computed
PubMed: 9799883
DOI: 10.1136/pgmj.74.872.321 -
Parasites & Vectors Mar 2022Taenia multiceps is a taeniid cestode that inhabits the small intestines of both wild and domestic carnivores. The larval stage, Coenurus cerebralis, is typically found... (Review)
Review
Taenia multiceps is a taeniid cestode that inhabits the small intestines of both wild and domestic carnivores. The larval stage, Coenurus cerebralis, is typically found in the central nervous system (CNS) of a wide range of livestock and, to a lesser extent, in the extra-cerebral tissues of sheep and goats. This review covers all aspects of the life cycle of T. multiceps and its epidemiology, molecular characterization, pathogenesis, diagnosis, therapy, control and zoonotic potential. Coenurosis caused by the larval stage of T. multiceps has a worldwide distribution and is often fatal in intermediate hosts, which can result in substantial economic losses in livestock farming. Molecular characterization using the mitochondrial genes cytochrome c oxidase subunit 1 and nicotinamide adenine dinucleotide dehydrogenase subunit 1 of different T. multiceps populations has revealed significant genetic variation and the presence of three major haplotypes. The disease mostly affects young sheep and is referred to as either acute or chronic coenurosis. Acute coenurosis occurs as a result of oncospheres migrating through the CNS, while chronic coenurosis occurs as a consequence of the coenurus maturing, which causes displacement and pressure atrophy of brain tissue. Non-cerebral coenurosis has been most commonly reported in goats. The best diagnostic method for cerebral coenurosis involves the interpretation of clinical signs with accurate localization of the cyst using diagnostic imaging techniques. A vaccine based on recombinant oncosphere antigens has proved to be an effective tool against T. multiceps infection in sheep. Additionally, use of anthelmintics during the parasite's migration stages reduces the development of cysts in the sheep brain. Surgery is considered the most effective method for the treatment of cerebral coenurosis in small ruminants, but is often not carried out because of the limited finances of many sheep and goat breeders. However, coenurosis can also be controlled effectively through preventative measures, such as anthelmintic treatment of dogs and the proper disposal of intermediate host carcasses. The parasite is also zoonotic, and cases of coenurosis have been reported in humans with coenuri located in the brain, spinal cord and eyes.
Topics: Animals; Cestoda; Cestode Infections; Cysticercosis; Dogs; Sheep; Sheep Diseases; Taenia
PubMed: 35279199
DOI: 10.1186/s13071-022-05210-0 -
PLoS Neglected Tropical Diseases Apr 2022Infections with the tapeworm Taenia solium (taeniosis and cysticercosis) are Neglected Tropical Diseases (NTD) highly endemic in Madagascar. These infections are however...
BACKGROUND
Infections with the tapeworm Taenia solium (taeniosis and cysticercosis) are Neglected Tropical Diseases (NTD) highly endemic in Madagascar. These infections are however underdiagnosed, underreported and their burden at the community level remains unknown especially in rural remote settings. This study aims at assessing the prevalence of T. solium infections and associated risk factors in twelve remote villages surrounding Ranomafana National Park (RNP), Ifanadiana District, Madagascar.
METHODOLOGY
A community based cross-sectional survey was conducted in June 2016. Stool and serum samples were collected from participants. Tapeworm carriers were identified by stool examination. Taenia species and T. solium genotypes were characterised by PCR and sequencing of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Detection of specific anti-cysticercal antibodies (IgG) or circulating cysticercal antigens was performed by ELISA or EITB/Western blot assays.
PRINCIPAL FINDINGS
Of the 459 participants with paired stool and blood samples included ten participants from seven distinct villages harbored Taenia spp. eggs in their stools samples DNA sequencing of the cox1 gene revealed a majority of T. solium Asian genotype (9/10) carriage. The overall seroprevalences of anti-cysticercal IgGs detected by ELISA and EITB were quite similar (27.5% and 29.8% respectively). A prevalence rate of 12.4% of circulating cysticercal antigens was observed reflecting cysticercosis with viable cysts. Open defecation (Odds Ratio, OR = 1.5, 95% CI: 1.0-2.3) and promiscuity with households of more than 4 people (OR = 1.9, 95% CI: 1.1-3.1) seem to be the main risk factors associated with anticysticercal antibodies detection. Being over 15 years of age would be a risk factor associated with an active cysticercosis (OR = 1.6, 95% CI: 1.0-2.7). Females (OR = 0.5, 95% CI: 0.3-0.9) and use of river as house water source (OR = 0.3, 95% CI: 0.1-1.5) were less likely to have cysticercosis with viable cysts.
CONCLUSIONS/SIGNIFICANCE
This study indicates a high exposure of the investigated population to T. solium infections with a high prevalence of cysticercosis with viable cysts. These data can be useful to strengthen public health interventions in these remote settings.
Topics: Animals; Cross-Sectional Studies; Cysticercosis; Cysticercus; Cysts; Female; Humans; Madagascar; Neglected Diseases; Prevalence; Rainforest; Swine; Swine Diseases; Taenia solium; Taeniasis
PubMed: 35404983
DOI: 10.1371/journal.pntd.0010265 -
Brain Pathology (Zurich, Switzerland) Jan 1997Echinococcosis is a human disease caused by the larval form of Taenia echinococcus, which lives in the gut of the dog, wild canides and other carnivorous animals which... (Review)
Review
Echinococcosis is a human disease caused by the larval form of Taenia echinococcus, which lives in the gut of the dog, wild canides and other carnivorous animals which represent the definitive hosts and involves as intermediate hosts both domestic and wild animals. Humans become accidental intermediate hosts by ingesting Taenia eggs. The main species pathogenic for man are E granulosus causing cystic echinococcosis with worldwide distribution and endemic in sheep and cattle breeding countries, and E multilocularis causing alveolar echinococcosis, with preferential distribution in the northern hemisphere. After ingestion of contaminated food, hexacanth embryos migrate by the portal system to liver and later lung, brain and other tissues. Symptoms are related to both cyst location and size. E granulosus infection of the central nervous system (CNS) may be primary or secondary and has been estimated to be low (2%). Sharply demarcated, spherical and intraparenchymal, cysts may reach a large size causing neurological symptoms. Spilling of cyst fluid due to trauma or surgery may trigger anaphylaxis as well as disseminated infection. Host reaction is minimal in the brain but a foreign giant cell reaction may develop. E multilocularis develops within the liver as a rapid invasive pseudomalignant growth and may metastasize to the CNS, where estimated incidence reaches 5%. Hydatid antigens induce an immune reaction in the host which is helpful for the diagnosis. DNA probes and PCR may be applied to differentiate between Echinococcus spp. Although the host develops an immunological protection from reinfection, the parasite evades host immune attack. A wide range of evasion mechanisms have been advanced, including a barrier for host cells due to hydatid cyst laminated cuticle, polyclonal activation of lymphocytes by parasite soluble antigens, and depression of host cell immune responses. Chronic stimulation of the host by cyst fluid antigens leads to increased specific IgG4 production, which might act as blocking antibodies against anaphlaxis suggestive of host response immunomodulation.
Topics: Animals; Central Nervous System Diseases; Echinococcosis; Host-Parasite Interactions; Humans; Immunologic Tests; Taenia; Zoonoses
PubMed: 9034573
DOI: 10.1111/j.1750-3639.1997.tb01082.x -
Brain Pathology (Zurich, Switzerland) Jan 1997Cysticercosis is an infection caused by Taenia solium larvae (cysticerci). When the cysticercus is lodged in the central nervous system (CNS), the disease is known as... (Review)
Review
Cysticercosis is an infection caused by Taenia solium larvae (cysticerci). When the cysticercus is lodged in the central nervous system (CNS), the disease is known as neurocysticercosis (NCC). NCC is the most frequent and most widely disseminated human neuroparasitosis. It is endemic in many parts of the world, particularly Latin America, Africa, and Asia, and still relatively frequent in Portugal, Spain and Eastern European countries It is also endemic in developed countries with high rates of immigration from endemic areas. Man may act as an intermediate host after ingestion of mature, viable T. solium eggs via the fecal-oral route. The development of lesions in the brain and leptomeninges, and the consequent of onset of symptoms associated with NCC are mainly due to the host immune-inflammatory response. As long as the cysticercus remains viable, there is relative host immune tolerance. It is only when the parasite dies that massive antigen exposure occurs, with intensification of the immune response/inflammatory reaction and the appearance or worsening of symptoms. NCC can be asymptomatic or cause widely varied clinical manifestations, such as seizures, increased intracranial pressure, ischemic cerebrovascular disease, dementia, and signs of compression of the spinal roots/cord. The combination of two or more symptoms is common. Such clinical polymorphism is determined by 1) the number of lesions (single or multiple cysticerci); 2) the location of CNS lesions (subarachnoid, intracerebral, intraventricular, intramedullary); 3) the type of cysticercus (Cysticercus cellulosae, Cysticercus racemosus); 4) the stage of development and involution of the parasite (vesicular or viable, necrotic, fibrocalcified nodule); and 5) the intensity of the host immune-inflammatory response (no inflammatory reaction, leptomeningitis, encephalitis, granular ependymitis, arteritis).
Topics: Animals; Central Nervous System Diseases; Cysticercosis; Host-Parasite Interactions; Humans; Mexico; Taenia
PubMed: 9034574
DOI: 10.1111/j.1750-3639.1997.tb01083.x -
Continuum (Minneapolis, Minn.) Dec 2012Neurocysticercosis occurs when humans become intermediate hosts in the life cycle of Taenia solium by ingesting its eggs directly from a taenia carrier or, less often,... (Review)
Review
PURPOSE OF REVIEW
Neurocysticercosis occurs when humans become intermediate hosts in the life cycle of Taenia solium by ingesting its eggs directly from a taenia carrier or, less often, by contaminated food. Within the nervous system, cysticerci may lodge in the brain parenchyma, subarachnoid space, ventricular system, or spinal cord, causing a number of pathologic changes that are responsible for the pleomorphism of neurocysticercosis. This article discusses the clinical manifestations, diagnosis, and treatment of neurocysticercosis.
RECENT FINDINGS
Formerly endemic in the developing world, mass immigration of people from disease-endemic to nonendemic areas has caused a recent increase in the prevalence of neurocysticercosis in developed countries, where this condition should no longer be considered exotic. Recent advances in neuroimaging and immune diagnostic methods, and the introduction of a set of diagnostic criteria, have enhanced the diagnostic accuracy for neurocysticercosis. Likewise, introduction of potent cysticidal drugs has radically changed its prognosis.
SUMMARY
Neurocysticercosis is the most common helminthic infection of the CNS and a major cause of acquired epilepsy worldwide. Diagnosis of neurocysticercosis is possible after interpretation of clinical data together with findings of neuroimaging studies and results of immunologic tests in a proper epidemiologic context. The use of cysticidal drugs reduces the burden of infection in the brain and improves the clinical course of most patients. Further efforts must be directed to eradicate the disease through the implementation of control programs against all interrelated steps in the life cycle of T. solium, including human carriers of the adult tapeworm, infected pigs, and eggs in the environment.
Topics: Animals; Anthelmintics; Antibody Formation; Cognition Disorders; Epilepsy; Female; Humans; Immunologic Tests; Intracranial Hypertension; Life Cycle Stages; Magnetic Resonance Imaging; Male; Middle Aged; Neurocysticercosis; Taenia solium; Tomography, X-Ray Computed; Young Adult
PubMed: 23221847
DOI: 10.1212/01.CON.0000423853.47770.90 -
Acta Tropica Feb 2017Neurocysticercosis (NCC) is the most common parasitic disease of the human central nervous system (CNS), a pleomorphic disease with a diverse array of clinical... (Review)
Review
Neurocysticercosis (NCC) is the most common parasitic disease of the human central nervous system (CNS), a pleomorphic disease with a diverse array of clinical manifestations. The infection is pleomorphic and dependent on a complex range of interconnecting factors, including number and size of the cysticerci, their stage of development and localisation within the brain with resulting difficulties in accurate diagnosis and staging of the disease. This review examines the factors that contribute to the accurate assessment of NCC distribution and transmission that are critical to achieving robust disease burden calculations. Control and prevention of T. solium transmission should be a key priority in global health as intervention can reduce the substantial healthcare and economic burdens inflicted by both NCC and taeniasis. Surveillance systems need to be better established, including implementing obligatory notification of cases. In the absence of reliable estimates of its global burden, NCC will remain-along with other endemic zoonoses, of low priority in the eyes of funding agencies-a truly neglected disease.
Topics: Animals; Anticestodal Agents; Anticonvulsants; Central Nervous System; Cysticercus; Glucocorticoids; Humans; Neglected Diseases; Neurocysticercosis; Taenia solium
PubMed: 27880878
DOI: 10.1016/j.actatropica.2016.11.015 -
Parasites & Vectors Jan 2021Taenia spp. are responsible for a substantial health and economic burden in affected populations. Knowledge of the fate of the eggs of Taenia spp. in the environment and... (Review)
Review
Taenia spp. are responsible for a substantial health and economic burden in affected populations. Knowledge of the fate of the eggs of Taenia spp. in the environment and of other factors facilitating the transmission of eggs to intermediate hosts is important for the control/elimination of infections caused by Taenia spp. The aim of this systematic review was to summarize current knowledge of the factors influencing the survival and dispersal of Taenia spp. eggs in the environment. Publications retrieved from international databases were systematically reviewed. Of the 1465 papers initially identified, data were ultimately extracted from 93 papers. The results of this systematic review indicate that survival is favoured at moderate temperatures (0-20 °C). Humidity seems to affect the survival of Taenia spp. eggs more than temperature. Under field circumstances, Taenia spp. eggs have been found to survive for up to 1 year. Taenia spp. eggs are commonly found on vegetables (0.9-30%) and in soil and water samples (0-43%), with their presence posing a risk to the consumer. Invertebrates may act as transport hosts, transferring the infection to an intermediate host, but the importance of this route of transmission is still open to question. Wastewater treatment systems are not capable of entirely eliminating Taenia spp. eggs. Access to surface water and the use of sewage sludge as fertilizer on pastures are important risk factors for bovine cysticercosis. Although information on the survival and spread of Taenia spp. eggs is available, in general the data retrieved and reviewed in this article were old, focused on very specific geographical regions and may not be relevant for other areas or not specific for different Taenia spp. Furthermore, it is unknown whether egg survival differs according to Taenia sp. Future studies are necessary to identify sustainable methods to identify and inactivate parasite eggs in the environment and reduce their spread.
Topics: Animal Distribution; Animals; Cattle; Communicable Disease Control; Cysticercosis; Humans; Humidity; Invertebrates; Life Cycle Stages; Longevity; Parasite Egg Count; Sewage; Soil; Taenia; Taeniasis; Temperature; Water Purification
PubMed: 33514421
DOI: 10.1186/s13071-021-04589-6 -
Parasites & Vectors Sep 2021Tapeworm infections are among the tropical neglected parasitic diseases endemically occurring in Ethiopia. This systematic review and meta-analysis aims at estimating... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Tapeworm infections are among the tropical neglected parasitic diseases endemically occurring in Ethiopia. This systematic review and meta-analysis aims at estimating the pooled prevalence and distribution of Taenia and Echinococcus infections in humans and animals from reports from Ethiopia.
METHODS
The systematic search was conducted in four bibliographic databases (PubMed, Google Scholar, Africa Journal Online and Science Direct). Additional data were retrieved from grey literature. Studies that met the inclusion criteria were considered for the systematic review and meta-analysis. The meta-analysis was conducted using MetaXL add-in for Microsoft Excel. Heterogeneity and inconsistency were evaluated using Cochran's Q and I statistics, respectively.
RESULTS
The study provides a country-based database of Taenia and Echinococcus infections consisting of 311 datasets from 201 publications which were mostly abattoir surveys; of these, 251 datasets were subjected to meta-analysis. Most of the studies were from Oromia (32.8%) followed by Amhara (22.9%) regional states. The pooled prevalence of cystic echinococcosis in intermediate and accidental hosts was calculated as 22% (95% CI 18-26%) and high study variability (Q = 24,420.65, I = 100%, P = 0.000). Moreover, a pooled prevalence of Echinococcus infections in final hosts was calculated as 33% (95% CI 20-48%) and low study variability (Q = 17.24, I = 65%, P = 0.001). Similarly, study subjects (human, cattle, sheep, goat and wolf) were infected by Taenia spp. with pooled prevalence of 3% (95% CI 2-4%) and moderate study variability (Q = 279.07, I = 89, P = 0.000). Meanwhile, the pooled prevalence of Taenia hydatigena, T. ovis and T. multiceps infections in intermediate hosts were calculated as 38%, 14% and 5%, respectively. The random effect meta-analysis of bovine cysticercosis showed a pooled prevalence of 7% (95% CI 5-9%) and high study variability was of (Q = 4458.76; I = 99%, P = 0.000). Significant differences in prevalence of Taenia and Echinococcus infections between study sites or different livestock origins have been reported.
CONCLUSION
The study evidenced a comprehensive dataset on the prevalence and distribution of Taenia and Echinococcus infections at different interfaces by regions and hosts and hence can aid in the design of more effective control strategies.
Topics: Abattoirs; Animals; Cattle; Echinococcosis; Ethiopia; Goats; Humans; Livestock; Prevalence; Taenia; Taeniasis
PubMed: 34488862
DOI: 10.1186/s13071-021-04925-w -
Parasite Immunology Aug 2014The life cycle of Taenia solium, the pork tapeworm, is continuously closed in many rural settings in developing countries when free roaming pigs ingest human stools... (Review)
Review
The life cycle of Taenia solium, the pork tapeworm, is continuously closed in many rural settings in developing countries when free roaming pigs ingest human stools containing T. solium eggs and develop cysticercosis, and humans ingest pork infected with cystic larvae and develop intestinal taeniasis, or may also accidentally acquire cysticercosis by faecal-oral contamination. Cysticercosis of the human nervous system, neurocysticercosis, is a major cause of seizures and other neurological morbidity in most of the world. The dynamics of exposure, infection and disease as well as the location of parasites result in a complex interaction which involves immune evasion mechanisms and involutive or progressive disease along time. Moreover, existing data are limited by the relative lack of animal models. This manuscript revises the available information on the immunology of human taeniasis and cysticercosis.
Topics: Animals; Cysticercosis; Host-Parasite Interactions; Humans; Life Cycle Stages; Meat; Swine; Swine Diseases; Taenia solium; Taeniasis
PubMed: 24962350
DOI: 10.1111/pim.12126