Page 1. Cysticercosis: Life Cycle of Taenia solium. Background: Taenia solium is a major cause of preventable epilepsy in .. minutes) of the T. solium lifecycle, methods of prevention and. Taenia solium is the so-called pork tapeworm belonging to cyclophyllid cestodes in the family It completes its life cycle in humans as the definitive host and often pigs as intermediate .. Create a book · Download as PDF · Printable version.
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Taenia spp. are long, segmented, parasitic tapeworms. • They have an indirect life cycle, cycling between a definitive and an intermediate host. Cestodes. Taenia Solium ▻Proglottid is smaller than T saginata and has Life Cycle. Infected tissue eaten by man. Cysticercus digested out of infected tissue. Request PDF on ResearchGate | Taenia solium: Biological Characteristics and Life Cycle | Taenia solium is one of the many species of cestodes (tapeworms).
Spermatozoa fuse with the ova in the fertilisation duct, where the zygotes are produced. The zygote undergoes holoblastic and unequal cleavage resulting in three cell types, small, medium and large micromeres, mesomeres, megameres. Megameres develop into a syncytial layer, the outer embryonic membrane; mesomeres into the radially striated inner embryonic membrane or embryophore; micromeres become the morula. The morula transforms into a six-hooked embryo known as an oncosphere, or hexacanth "six hooked" larva.
A gravid proglottid can contain more than 50, embryonated eggs.
Gravid proglottids often rupture in the intestine, liberating the oncospheres in faeces. Intact gravid proglottids are shed off in groups of four or five. The free eggs and detached proglottids are spread through the host's defecation peristalsis. Oncospheres can survive in the environment for up to two months.
The embryonated eggs enter intestine where they hatch into motile oncospheres. The embryonic and basement membranes are removed by the host's digestive enzymes particularly pepsin. Then the free oncospheres attach on the intestinal wall using their hooks. With the help of digestive enzymes from the penetration glands, they penetrate the intestinal mucosa to enter blood and lymphatic vessels.
They move along the general circulatory system to various organs, and large numbers are cleared in the liver. The surviving oncospheres preferentially migrate to striated muscles , as well as the brain , liver, and other tissues, where they settle to form cysts — cysticerci. The central space is filled with fluid like a bladder , hence it is also called bladder worm. Cysticerci are usually formed within 70 days and may continue to grow for a year.
As in pigs, the oncospheres hatch and enter blood circulation. When they settle to form cysts, clinical symptoms of cysticercosis appear. The cysticercus is often called the metacestode. Main articles: Cysticercosis and Taeniasis Intestinal infection of T. Only in severe cases, conditions of intestinal irritation, anaemia , and indigestion occur, which can lead to loss of appetite and emaciation.
Cysticercus is clinically pathogenic. Ingestion of T. This is the most frequent and severe disease caused by T. In symptomatic cases, a wide spectrum of symptoms may be expressed, including headaches, dizziness, and occasional seizures. In more severe cases, dementia or hypertension can occur due to perturbation of the normal circulation of cerebrospinal fluid.
Any increase in intracranial pressure will result in a corresponding increase in arterial blood pressure , as the body seeks to maintain circulation to the brain. The severity of cysticercosis depends on location, size and number of parasite larvae in tissues, as well as the host immune response.
Do you perform a T. How do you handle T. Which antibody detecting methods do you use to approach T. What kind of antigen do you use in your in-house antibody detection test?
Do you use microscopic methods to approach T. Do you observe any relevant cross reactions in your cysticercosis antibody tests? Do you use molecular methods to approach T. Which antigen detection methods do you use to approach T.
What kind of antibodies do you use in your in-house test? Do you observe any relevant cross reactions in your T. Do you observe any relevant cross reaction in your cysticercosis antigen tests?
If you use any other test for T. Are there national ring-trials in your country to ascertain the quality of your T. Would you be interested in participating in a European ring trial for T. Do you have diagnostic tests for other Taenia spp. Do you observe any relevant cross reactions in T. Post mortems undertaken at the end of the trial involved the same procedures, such that direct comparisons could be made between results from the two sets of data.
However, for all animals in which no cysticerci were found during the post mortems carried out at the end of the trial, the remaining musculature left hand side carcase was also sliced. In the case of the animals from the intervention area, none was recorded as having any cysts in the entire carcase musculature or other tissues that were examined. In the 36 control animals, two additional infected animals were identified, one having a single viable cyst and the other having two viable cysts in the left hand side musculature, but no cysts elsewhere.
In this group of 36 infected animals from the control area most had light infections.
Chembensofu et al. During the post mortems all carcase lesions and lesions in the brain, liver, kidneys and lungs were examined for the presence of a cysticercus. No cysticerci were found other than in striated muscle tissue and the brain. Necrotic lesions and other suspect lesions were investigated for the presence of taeniid or T.
These data are consistent with the tissue distribution of T.
These data, however, contrast with those reported by Chembensofu et al. There is no clear explanation for this discrepancy. Potentially effective control measures for T. Feasibility and sustainability of control measures have been the stumbling block to controlling T.
The requirement for a day withholding period after oxfendazole treatment of pigs, creation of necrotic lesions in the meat of drug-treated, infected pigs, and difficulties with reliably predicting the time of sale or slaughter, prevent a treat-immediately-before-slaughter approach being used in pigs to control T. To be effective, the frequency with which intervention would need to be undertaken in the pig population is governed by the rapid turnover of pigs in the communities and constant introduction of new, susceptible animals into the population due to pigs breeding throughout the year.
Combining both vaccination and oxfendazole as a preventative treatment for porcine cysticercosis has several advantages. Secondly, the drug treats many nematode and trematode infections, as well as cysticercosis, likely providing a health and productivity boost to the treated animals [ 23 , 24 ].
Oxfendazole treatment does not provide any protection for uninfected pigs against subsequent exposure to the T.
After treatment of an infected pigs with oxfendazole necrotic lesions are evident in the musculature for a period of at least several weeks; the great majority disappearing within a period of 3 months [ 6 , 24 , 25 ]. It seems likely that some of the animals from the intervention area in Nepal that underwent post mortem investigation would have been infected with T. However no non-viable lesions were detected in the muscles of the animals that had participated in the interventions.
The three-monthly treatment regime that was implemented in the trial appears to have allowed sufficient time for any lesions that were the result of the death of parasites in muscles after medication to be resorbed before the animals reached slaughter age. A limitation to the use of oxfendazole as a treatment for porcine cysticercosis is the requirement for a 3 week withholding period after treatment before slaughter due to the presence of drug residues in the tissues [ 9 ].
Farmers were requested to not sell or kill the treated animals for 3 weeks after each treatment. This imposes a significant burden on the farmers, especially when the procedure is repeated every 3 months, and it is difficult to monitor compliance.