Relationship between Serum Antibodies and Taenia solium Larvae Burden in Pigs Raised in Field Conditions

Gavidia, C César; Verástegui, Manuela; Garcı́a, Héctor H.; López-Urbina, María T.; Tsang, Victor C. W.; Pan, William; Gilman, Robert H.; González, Armando E.

doi:10.1371/journal.pntd.0002192

Cited by 27 publications

(35 citation statements)

References 33 publications

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“…17 We attempted to purchase all seropositive pigs that had three or more reactive bands on Western blot analysis for necropsy, because prior necropsies showed that the most viable infections occurred in this group. 18 We also included a random 10% sample of seropositive pigs that had one or two reactive bands on Western blot analysis.…”

Section: Methodsmentioning

confidence: 99%

Elimination ofTaenia soliumTransmission in Northern Peru

et al. 2016

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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.)

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Section: Methodsmentioning

confidence: 99%

Elimination ofTaenia soliumTransmission in Northern Peru

et al. 2016

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“…They cannot distinguish between patent infection and exposure, although strong reactions may be associated with established infection and higher parasitic burden. [11][12][13] Detection of specific circulating antigens can reflect presence and burden of patent infection. [14][15][16][17] Cysticercosis antigen detection assays were reported as early as of 1989, using a monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA) directed to a secretoryexcretory antigen from the related cestode Taenia saginata.…”

Section: Introductionmentioning

confidence: 99%

Successful Antiparasitic Treatment for Cysticercosis is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model

González

Bustos

Garcı́a

et al. 2015

The American Society of Tropical Medicine and Hygiene

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Abstract. Taenia solium cysticercosis is a common parasitic infection of humans and pigs. We evaluated the posttreatment evolution of circulating parasite-specific antigen titers in 693 consecutive blood samples from 50 naturally infected cysticercotic pigs, which received different regimes of antiparasitic drugs (N = 39, 7 groups), prednisone (N = 5), or controls (N = 6). Samples were collected from baseline to week 10 after treatment, when pigs were euthanized and carefully dissected at necropsy. Antigen levels decreased proportionally to the efficacy of treatment and correlated with the remaining viable cysts at necropsy (Pearson's p = 0.67, P = 0.000). A decrease of 5 times in antigen levels (logarithmic scale) compared with baseline was found in 20/26 pigs free of cysts at necropsy, compared with 1/24 of those who had persisting viable cysts (odds ratio [OR] = 76.7, 95% confidence interval [CI] = 8

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“…It is important to recognize that a positive result on the EITB LLGP does not necessarily indicate active infection [30]. A positive result can occur from exposure to T. solium eggs that did not result in established infection, from previously established infection which has been cleared or by transmission of maternal antibodies in colostrum [31], [32].…”

Section: Discussionmentioning

confidence: 99%

Ring-Screening to Control Endemic Transmission of Taenia solium

et al. 2014

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Background Taenia solium is a major cause of preventable epilepsy in developing nations. Screening and treatment of human intestinal stage infection (taeniasis) within high-risk foci may reduce transmission and prevent epilepsy by limiting human exposure to infective eggs. We piloted a ring-strategy that involves screening and treatment for taeniasis among households located nearby pigs heavily-infected with the larval stage (cysticercosis). These pigs mark areas of increased transmission and can be identified by tongue examination.MethodologyWe selected two villages in northern Peru for a controlled prospective interventional cohort pilot study. In the intervention village (1,058 residents) we examined the tongues of all pigs every 4 months for nodules characteristic of cysticercosis. We then screened all residents living within 100-meters of any tongue-positive pig using enzyme-linked immunosorbent assay to detect Taenia antigens in stool. Residents with taeniasis were treated with niclosamide. In both the intervention and control (753 residents) we measured incidence of exposure by sampling the pig population every 4 months for serum antibodies against cysticercosis using enzyme-linked immunoelectrotransfer blot.Principal FindingsBaseline seroincidence among pigs born during the study was 22.6 cases per 100 pigs per-month (95% confidence interval [CI] 17.0–30.0) in the intervention and 18.1 (95% CI 12.7–25.9) in the control. After one year we observed a 41% reduction in seroincidence in the intervention village compared to baseline (incidence rate ratio 0.59, 95% CI 0.41–0.87) while the seroincidence in the control village remained unchanged. At study end, the prevalence of taeniasis was nearly 4 times lower in the intervention than in the control (prevalence ratio 0.28, 95% CI 0.08–0.91).Conclusions/SignificanceRing-screening reduced transmission of T. solium in this pilot study and may provide an effective and practical approach for regions where resources are limited. However, this strategy requires validation in larger populations over a greater period of time.

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Relationship between Serum Antibodies and Taenia solium Larvae Burden in Pigs Raised in Field Conditions

Cited by 27 publications

References 33 publications

Elimination ofTaenia soliumTransmission in Northern Peru

Elimination ofTaenia soliumTransmission in Northern Peru

Successful Antiparasitic Treatment for Cysticercosis is Associated with a Fast and Marked Reduction of Circulating Antigen Levels in a Naturally Infected Pig Model

Ring-Screening to Control Endemic Transmission of Taenia solium

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