| Yan Jin | 12 Articles |
Toxoplasma gondii is an intracellular protozoan parasite capable of causing chronic infection by forming persistent cysts in the brain. Despite its global burden, no approved vaccine exists. Virus-like particle vaccines expressing microneme protein 8 (MIC8) or apical membrane antigen 1 (AMA1) of T. gondii have previously shown efficacy. In this study, we generated recombinant vaccinia viruses (rVVs) expressing MIC8 and AMA1 and evaluated their efficacy against T. gondii ME49 infection. BALB/c mice were intramuscularly immunized with a combination of MIC8 and AMA1 rVVs and challenged orally with T. gondii ME49. Immunization with MIC8+AMA1 rVVs produced a significant increase in T. gondii-specific IgG. Splenocyte analysis revealed robust activation of CD4+ and CD8+ T cells, as well as expansion of memory B cells. The immunized group exhibited an 89.6% reduction in brain cyst count, with significantly improved survival compared to the control group. These findings demonstrate that combining the antigens MIC8 and AMA1 using a vaccinia virus platform can effectively promote both humoral and cellular immunity, supporting its potential as a vaccine strategy against T. gondii ME49.
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Schistosomiasis remains one of the most prevalent neglected tropical diseases in Tanzania. World Vision Tanzania, in collaboration with the Ministry of Health through the National Neglected Tropical Diseases Control Programme, implemented school- and community-based mass drug administrations, community-led total sanitation, and community voice and action from 2020 to 2022. This study assessed changes in the prevalence of schistosomiasis in the Itilima district of northwestern Tanzania following the implementation of these integrated interventions. A total of 1,405 students from 22 schools participated in the baseline survey in August to September 2020, and 1,320 in September 2022. Additionally, 368 adults from 8 villages participated in the baseline survey, and 401 in the endline survey. The prevalence difference was calculated to assess changes before and after the integrated interventions. We also investigated risk factors for Schistosoma haematobium infection using endline data. The prevalence difference between 2020 and 2022 was -20.0% (95% confidence interval (CI)=-22.2%–-17.7%, p<0.001) for students and -19.6% (95% CI=-22.2%–-17.7%, p<0.001) for adults. Individuals without a latrine were more likely to have schistosomiasis (adjusted odds ratio=5.9, 95% CI=1.7–21.5, p=0.01) compared to those who had a latrine. The findings indicate substantial changes in schistosomiasis prevalence in the study area following the implementation of integrated interventions. To sustain these achievements in Itilima, a multi-sectorial approach is highly recommended to integrate additional measures for eliminating schistosomiasis as a public health problem.
Hymenolepis nana, commonly known as the dwarf tapeworm, affects 50 to 75 million people worldwide. To date, no studies have explored the disease burden of H. nana infection in Sudan. This study aimed to determine the national prevalence of H. nana across 189 districts and 18 states in Sudan and the number of individuals infected with H. nana who did not receive treatment during the mass drug administration (MDA) campaign targeting schistosomiasis. In addition, the study sought to evaluate the extent of co-infection of H. nana with schistosomiasis and soil-transmitted helminthiasis. This involved a secondary analysis of a nationwide survey conducted in 2017 in Sudan. Binomial family generalized linear models with a logarithmic link function were used to estimate the prevalence ratio of potential risk factors, including sex and water and sanitation conditions in schools and households. For the nationwide survey, a 2-stage sampling method was used, in which 105,167 students were selected from 1,772 schools. A total of 96,679 stool samples were collected, of which 4,706 (4.9%) tested positive for H. nana. Of these, fewer than 1% were co-infected with schistosomiasis (either Schistosoma haematobium or Schistosoma mansoni), and a mere 0.1% had co-infections with soil-transmitted helminths. At an 8% threshold for village-based MDA, approximately 1.1 million infected adults are ineligible to receive praziquantel from the village-based MDA. Children residing in households with improved latrines had a lower odds of H. nana infection than those without improved latrines did (adjusted odds ratio=0.87, 95% confidence interval=0.80–0.94, p=0.001). In countries where H. nana is endemic, such as Sudan, providers making MDA decisions should consider the prevalence of either H. nana or schistosomiasis, rather than focusing solely on the latter.
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We investigated organ specific Toxocara canis larval migration in mice infected with T. canis larvae. We observed the worm burden and systemic immune responses. Three groups of BALB/c mice (n=5 each) were orally administered 1,000 T. canis 2nd stage larvae to induce larva migrans. Mice were sacrificed at 1, 3, and 5 weeks post-infection. Liver, lung, brain, and eye tissues were collected. Tissue from 2 mice per group was digested for larval count, while the remaining 3 mice underwent histological analysis. Blood hematology and serology were evaluated and compared to that in a control uninfected group (n=5) to assess the immune response. Cytokine levels in bronchoalveolar lavage (BAL) fluid were also analyzed. We found that, 1 week post-infection, the mean parasite load in the liver (72±7.1), brain (31±4.2), lungs (20±5.7), and eyes (2±0) peaked and stayed constant until the 3 weeks. By 5-week post-infection, the worm burden in the liver and lungs significantly decreased to 10±4.2 and 9±5.7, respectively, while they remained relatively stable in the brain and eyes (18±4.2 and 1±0, respectively). Interestingly, ocular larvae resided in all retinal layers, without notable inflammation in outer retina. Mice infected with T. canis exhibited elevated levels of neutrophils, monocytes, eosinophils, and immunoglobulin E. At 5 weeks post-infection, interleukin (IL)-5 and IL-13 levels were elevated in BAL fluid. Whereas IL-4, IL-10, IL-17, and interferon-γ levels in BAL fluid were similar to that in controls. Our findings demonstrate that a small portion of T. canis larvae migrate to the eyes and brain within the first week of infection. Minimal tissue inflammation was observed, probably due to increase of anti-inflammatory cytokines. This study contributes to our understanding of the histological and immunological responses to T. canis infection in mice, which may have implications to further understand human toxocariasis.
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In several schistosomiasis-endemic countries, the prevalence has remained high in some areas owing to reinfection despite repeated mass drug administration (MDA) interventions; these areas are referred to as persistent hot spots. Identifying hotspots is critical for interrupting transmission. This study aimed to determine an effective means of identifying persistent hot spots. First, we investigated the differences between Schistosoma haematobium and Schistosoma mansoni prevalence among school-aged children (SAC) estimated by a community-based survey, for which local key informants purposively selected communities, and a randomly sampled school-based survey. A total of 6,225 individuals residing in 60 villages in 8 districts of North Kordofan, Blue Nile, or Sennar States, Sudan participated in a community-based survey in March 2018. Additionally, the data of 3,959 students attending 71 schools in the same 8 districts were extracted from a nationwide school-based survey conducted in January 2017. The community-based survey identified 3 districts wherein the prevalence of S. haematobium or S. mansoni infection among SAC was significantly higher than that determined by the randomly sampled school survey (e.g., S. haematobium in the Sennar district: 10.8% vs. 1.1%, P<0.001). At the state level, the prevalence of schistosomiasis among SAC, as determined by the community-based survey, was consistently significantly higher than that determined by the school-based survey. Purposeful selection of villages or schools based on a history of MDA, latrine coverage, open defecation, and the prevalence of bloody urine improved the ability for identifying persistent hot spots.
Global efforts to identify groups at high risk for schistosomiasis have mainly concentrated on identifying their geographical distribution. Investigations on the socioeconomic characteristics of high-risk groups are relatively scarce. This study aimed to explore the associations between schistosomiasis among students and their parents’ occupations. A nationwide cross-sectional survey was conducted targeting 105,167 students in 1,772 primary schools across Sudan in 2017. From these students, 100,726 urine and 96,634 stool samples were collected to test for Schistosoma haematobium and S. mansoni infection. A multi-level mixed effect analysis was used with age and sex as fixed factors, and school as a random factor. The odd ratios (ORs) of practicing open defecation among farmers’ children were almost 5 times higher than their counterparts whose parents were government officials (OR=4.97, 95% confidence intervals (CIs): 4.57-5.42, P<0.001). The ORs of contacting water bodies for watering livestock among farmers’ children were more than 4 times higher than those of children whose parents were government officials (OR=4.59, 95% CIs: 4.02-5.24, P<0.001). This study shows that schistosomiasis represents a disease of poverty and that farmers’ children constituted a high-risk group.
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We aimed to explore the population dynamics of snail in 3 sites of the White Nile in Sudan. More specifically, we aimed to investigate the annual patterns of snail populations that act as intermediate hosts of schistosomes and monthly snail infection rates and ecological characteristics presumably related to snail populations. We collected snails for 1 year monthly at 3 different shore sites in the vicinity of El Shajara along the White Nile river in Khartoum State, Sudan. In addition, we measured air and water temperatures, water turbidities, vegetation coverages, and water depths and current speeds. Most of the collected snails were Biomphalaria pfeifferi and Bulinus truncatus. The population densities of snails and their infection rates varied across survey sites. The collected snails liberated S. mansoni and S. haematobium cercariae as well as Amphistome and Echinostome cercariae. Infected snails were found during March-June. The ecological characteristics found to be associated with the absence of snails population were: high turbidity, deep water, low vegetation coverage (near absence of vegetation), high water temperature, and high current speed. To our knowledge, this is the first longitudinal study of the snail population and ecological characteristics in the main basin of the White Nile river.
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Eosinophilia occurs commonly in many diseases including allergic diseases and helminthic infections. Toxocariasis has been suggested as one cause of eosinophilia. The present study was undertaken to examine the prevalence of toxocariasis in patients with eosinophilia and to identify the risk factors for toxocariasis. This prospective cohort study recruited a total of 81 patients with eosinophilia (34 males and 47 females) who visited the outpatient clinic at Seoul National University Hospital from January 2017 to February 2018 and agreed to participate in this study. The prevalence of toxocariasis was examined by T. canis-specific ELISA, and the various risk factors for toxocariasis were evaluated by a questionnaire survey. Among 81 patients with eosinophilia, 18 were positive for anti-T. canis antibodies (22.2%); 88.9% were male (16/18) and 11.1% were female (2/18). Multivariate statistical analysis revealed that males (OR 21.876, 95% CI: 1.667-287.144) with a history of consuming the raw meat or livers of animals (OR 5.899, 95% CI: 1.004-34.669) and a heavy alcohol-drinking habit (OR 8.767, 95% CI: 1.018-75.497) were at higher risk of toxocariasis in patients with eosinophilia. Toxocariasis should be considered a potential cause of eosinophilia when the patient has a history of eating the raw meat or livers of animals in Korea. A single course of albendazole is recommended to reduce the migration of Toxocara larvae in serologically positive cases with eosinophilia.
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Clonorchis sinensis is a Group-I bio-carcinogen, associated with cholangiocarcinoma (CCA). The hamster is the only experimental model of C. sinensis-mediated CCA, but we oblige another animal model. The present study intended to develop a C. sinensis (Cs) mediated CCA model using C3H/He mice, co-stimulated with N-nitrosodimethyl-amine (NDMA) and dicyclanil (DC). The mice were divided into 8 groups with different combinations of Cs, NDMA, and DC. Six months later the mice were sacrificed and subjected to gross and histopathological examination. The body weights were significantly reduced among the groups treated with 2 or more agents (eg. Cs+NDMA, Cs+DC, NDMA+DC, and Cs+NDMA+DC). In contrast, liver weight percentages to body weight were increased in above groups by 4.1% to 4.7%. A Change of the spleen weight was observed only in Cs+NDMA group. Though C. sinensis infection is evident from hyperplastic changes, only 1 worm was recovered. T wo mice, 1 from Cs and the other from Cs+DC group, showed mass forming lesions; 1 (281.2 mm3) from the Cs group was a hepatocellular adenoma and the other (280.6 mm3) from the Cs+DC group was a cystic mass (peliosis). Higher prevalence of gray-white nodules was observed in Cs group (42.9%) followed by Cs+NDMA+DC group (21.4%). The mice of the Cs+NDMA+DC group showed hyper-proliferation of the bile duct with fibrotic changes. No characteristic change for CCA was recognized in any of the groups. In conclusion, C3H/He mice produce no CCA but extensive fibrosis when they are challenged by Cs, NDMA, and DC together.
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Toxocariasis is a worldwide zoonosis caused by larvae of ascarid nematodes of dogs or cats, Citations Citations to this article as recorded by
According to increase of travel, the cases of imported echinococcosis have been increasing in Korea. The present study was undertaken to develop a serodiagnostic system for echinococcosis in Korea. For diagnosis of echinococcosis, the fluid of Citations Citations to this article as recorded by
Uzbekistan is endemic of cystic echinococcosis (CE). In order to estimate endemicity of CE, we collected data from emergency surgery due to CE in 2002-2010 and also investigated the prevalence of hydatid cysts in the liver and lungs of sheep at an abattoir in Uzbekistan from July 2009 to June 2010. In 14 emergency hospitals, 8,014 patients received surgical removal or drainage of CE during 2002-2010, and 2,966 patients were found in 2010. A total of 22,959 sheep were grossly examined of their liver and lungs, and 479 (2.1%) and 340 (1.5%) of them were positive for the cyst in the liver and lungs, respectively. Citations Citations to this article as recorded by
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