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Belizario VY,J, de Cadiz AE, Navarro RC, Flores MJC, Molina VB, Dalisay SNM, Medina JRC, Lumangaya CR. The status of schistosomiasis japonica control in the Philippines: The need for an integrated approach to address a multidimensional problem. INTERNATIONAL JOURNAL OF ONE HEALTH 2022. [DOI: 10.14202/ijoh.2022.8-19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Schistosomiasis japonica remains a public health concern in many areas of the Philippines. Adequate and updated information is essential to enhance policy and service delivery toward control and elimination. Despite the efforts on schistosomiasis control in the Philippines, some challenges remain in these dimensions. An integrated surveillance system is recommended to determine the prevalence of infection in humans, animal reservoirs, and snail intermediate hosts, allowing the identification of high-priority areas for targeted interventions. This will entail the enhancement of laboratory diagnosis capacity through the use of more sensitive techniques, complemented by capacity building of concerned human and animal health professionals. Given the zoonotic nature of schistosomiasis japonica, adopting the One Health approach is essential to influence policies and interventions that may accelerate control and elimination. This can be achieved through the attainment of mass drug administration coverage targets and intensified case finding and management, robust implementation and integration of veterinary public health activities, the conduct of snail control measures, provision of safe water, sanitation, and hygiene services, and health promotion and education into the national schistosomiasis control and elimination program. This review aimed to describe the status of schistosomiasis japonica control in the Philippines in the context of human health, animal health, vector ecology and management, environmental health, and sociocultural dimensions.
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Affiliation(s)
- Vicente Y. , Jr. Belizario
- Department of Parasitology, College of Public Health, University of the Philippines, Manila, Philippines; Neglected Tropical Diseases Study Group, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Aleyla E. de Cadiz
- Department of Biological Sciences and Environmental Studies, College of Science and Mathematics, University of the Philippines, Mindanao, Philippines
| | - Rohani C. Navarro
- National Institute of Molecular Biology and Biotechnology, National Institutes of Health, University of the Philippines, Manila, Philippines
| | - Mary Jane C. Flores
- Department of Biology, College of Science, De La Salle University, Manila, Philippines
| | - Victorio B. Molina
- Department of Environmental and Occupational Health, College of Public Health, University of the Philippines, Manila, Philippines
| | - Soledad Natalia M. Dalisay
- Department of Anthropology, College of Social Sciences and Philosophy, University of the Philippines, Diliman, Philippines
| | - John Robert C. Medina
- Department of Epidemiology and Biostatistics, College of Public Health, University of the Philippines, Manila, Philippines
| | - Carlo R. Lumangaya
- Neglected Tropical Diseases Study Group, National Institutes of Health, University of the Philippines, Manila, Philippines
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Green AE, Anchang-Kimbi JK, Wepnje GB, Ndassi VD, Kimbi HK. Distribution and factors associated with urogenital schistosomiasis in the Tiko Health District, a semi-urban setting, South West Region, Cameroon. Infect Dis Poverty 2021; 10:49. [PMID: 33845904 PMCID: PMC8042887 DOI: 10.1186/s40249-021-00827-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 03/16/2021] [Indexed: 12/11/2022] Open
Abstract
Background Increased risk of schistosomiasis in peri-urban and urban towns is not uncommon. An epidemiological survey was carried out in the Tiko Health District (THD), an unmapped transmission focus for urogenital schistosomiasis (UGS), to assess the distribution, intensity, and risk factors associated with the occurrence of UGS. Methods In this cross-sectional survey, 12 communities were purposively selected from four health areas (HAs) (Likomba, Holforth, Holforth-Likomba, and Mutengene) in South West Region of Cameroon between June and August 2018. Consenting individuals were enrolled using a convenient sampling technique and administered a semi-structured questionnaire to document information on socio-demographic and water contact behaviour. Urine samples were examined for Schistosomahaematobium infection using test strip, filtration, and microscopy methods. Bivariate and binary logistic regression analyses were used to identify predictors of infection. Results The overall prevalence of UGS in Likomba, Holforth-Likomba and Holforth was 31.5% [95% confidence interval (CI): 28.3–34.8] with geometric mean (GM) egg count of 28.7 (range: 2–450) eggs per 10 ml of urine. S.haematobium infection was not found in Mutengene HA. Infection was unevenly distributed among the HAs, Holforth-Likomba and Holforth being the most and least affected, respectively. The prevalence of infection varied (P < 0.001) among the affected communities, ranging from 12.0 to 56.9%. Infection status of the community related positively (P < 0.001) with proximity to stream (< 100 m), the degree of contact with water and number of improved water sources. Younger age group (5–14 years) [adjusted odds ratio (aOR): 3.7, 95% CI: 1.1–12.2] and intense water contact (degree II) (aOR: 5.2, 95% CI: 3.4–8.1) were associated with increased risk of infection. Similarly, significantly higher egg load was observed among younger aged groups (P = 0.02) and those who carried out intense water contact activities (P < 0.001). Conclusions Generally, THD is a moderate risk endemic focus for UGS but prevalence higher than 50.0% was observed in some communities. These findings warrant immediate mass chemotherapy with praziquantel to reduce morbidity. Provision of portable water and health education are proposed measures to reduce and eventually eliminate transmission in the area. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s40249-021-00827-2.
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Affiliation(s)
- Adeline Enjema Green
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.
| | - Judith Kuoh Anchang-Kimbi
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Godlove Bunda Wepnje
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Vicky Daonyle Ndassi
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon
| | - Helen Kuokuo Kimbi
- Department of Zoology and Animal Physiology, Faculty of Science, University of Buea, P.O. Box 63, Buea, Cameroon.,Department of Medical Laboratory Sciences, Faculty of Health Sciences, The University of Bamenda, P.O. Box 39, Bambili, Cameroon
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Abstract
Over the past 20 years, RNAS+ has been generating research results from highly collaborative projects meant to promote and advance understanding in various aspects of schistosomiasis. Epidemiological studies in endemic countries like the Philippines, the People's Republic of China (PR China), the Lao People's Democratic Republic (Lao PDR) and Cambodia clarified the role of reservoir hosts in transmission and the use of spatio-temporal methods such as remote sensing and geographical information systems (GIS) in surveillance of schistosomiasis. Morbidity studies proposed factors that might influence development of fibrosis, anaemia and malnutrition in schistosomiasis. Immune responses in schistosomiasis continue to be an interesting focus in research to explain possible development of resistance with age. Results of evaluation of candidate vaccine molecules are also presented. New diagnostics are continually being developed in response to the call for more sensitive and field applicable techniques that will be used for surveillance in areas nearing elimination of the disease. Several studies presented here show the insufficiency of mass drug administration (MDA) with praziquantel in eliminating the disease. Emphasis is given to an integrated control approach that can be accomplished through intensive and extensive intersectoral collaboration.
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Wang XY, He J, Juma S, Kabole F, Guo JG, Dai JR, Li W, Yang K. Efficacy of China-made praziquantel for treatment of Schistosomiasis haematobium in Africa: A randomized controlled trial. PLoS Negl Trop Dis 2019; 13:e0007238. [PMID: 30969960 PMCID: PMC6476521 DOI: 10.1371/journal.pntd.0007238] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Revised: 04/22/2019] [Accepted: 02/12/2019] [Indexed: 11/21/2022] Open
Abstract
Background In the roadmap on the neglected tropical diseases (NTD) the World Health Organization (WHO) aims at attaining at least 75% coverage of preventive chemotherapy in pre-school and school-age children by 2020. A randomized controlled trial was used to compare the effectiveness of praziquantel in treating Schistosoma haematobium in Africa using two different sources for the drug, Merck Limited Partnership (KgaA), Germany and Nanjing Pharmaceutical Factory (NPF), China. Methods More than 6,000 participants testing positive for S. haematobium infection were enrolled from three villages (shehias) situated in the northern, middle and southern part of Pemba Island, Zanzibar. Applying criteria of inclusion and exclusion, resulted in a study population of 152 people (84 males, 68 females). A randomized controlled trial was conducted assigning participants to either praziquantel from NPF or Merck KGaA. After one month, the cure rate of S. haematobium and adverse events were compared to evaluate effectiveness. The ratio of male to female, the ratio of light/high infection intensity, and the average value of age were calculated between the two drug manufacturers. Chi-squared test and T-test were used for consistency analysis. Results Out of the total of 73 cases receiving praziquantel from NPF, the cure rate achieved was 97.3% (73/75), while the 74 cases receiving the drug from Merck KgaA reached a similar cure rate (96.1% or 74/77). There was no significant difference between the two outcomes (χ2 = 0.003, P = 0.956). Among the 75 patients treat, only one (a 16-years old female student), who had received the drug made in China had slight adverse reactions manifested as dizziness, headache and abdominal pain. Conclusion The efficacy of China-made praziquantel does not differ significantly from praziquantel made by Merck KGaA in Germany. Trial registration ClinicalTrials.gov, NCT03133832 Schistosomiasis is a neglected tropical disease (NTD) with praziquantel the only effective drug available. It is estimated that about 800 million people are currently at risk for this disease with more than 200 million people infected. A large drug donation partnership between Merck, Darmstadt, Germany and the World Health Organization supports widespread, successful preventive chemotherapy programs, but the donated drugs does not meet the entire need, particularly not in Africa. The primary aim of our study was to evaluate the efficacy of China-made praziquantel to explore whether the drug could complement preventive chemotherapy programs in Africa. A randomized controlled trial was conducted assigning participants to two groups, one receiving praziquantel from NPF, the other from Merck KGaA. After one month, the cure rate of S. haematobium and were compared to evaluate effectiveness and document potential adverse events. The outcome showed that the two sources of praziquantel that did not differ significantly from each other. China-made praziquantel can thus be trusted to complement the current use of the drug from Merck KGaA in Africa making it possible to enlarge drug provision programs.
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Affiliation(s)
- Xin-Yao Wang
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, China
- Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health; Jiangsu Provincial Key Laboratory on the Molecular Biology of Parasites, Wuxi, Jiangsu, China
- College of Medicine, Jiangnan University, Wuxi, Jiangsu, China
| | - Jian He
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, China
- Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health; Jiangsu Provincial Key Laboratory on the Molecular Biology of Parasites, Wuxi, Jiangsu, China
- College of Medicine, Jiangnan University, Wuxi, Jiangsu, China
| | - Saleh Juma
- Ministry of Health of Zanzibar, Zanzibar, United Republic of Tanzania
| | - Fatma Kabole
- Ministry of Health of Zanzibar, Zanzibar, United Republic of Tanzania
| | - Jia-gang Guo
- Department of control of Neglected Tropical Diseases, World Health Organization, Geneva, Switzerland
| | - Jian-Rong Dai
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, China
- Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health; Jiangsu Provincial Key Laboratory on the Molecular Biology of Parasites, Wuxi, Jiangsu, China
| | - Wei Li
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, China
- Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health; Jiangsu Provincial Key Laboratory on the Molecular Biology of Parasites, Wuxi, Jiangsu, China
| | - Kun Yang
- Jiangsu Institute of Parasitic Diseases, Wuxi, Jiangsu, China
- Key Laboratory on Technology for Parasitic Disease Prevention and Control, Ministry of Health; Jiangsu Provincial Key Laboratory on the Molecular Biology of Parasites, Wuxi, Jiangsu, China
- College of Medicine, Jiangnan University, Wuxi, Jiangsu, China
- * E-mail:
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Mass drug administration and the global control of schistosomiasis: successes, limitations and clinical outcomes. Curr Opin Infect Dis 2018; 29:595-608. [PMID: 27584590 DOI: 10.1097/qco.0000000000000312] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
PURPOSE OF REVIEW Preventive chemotherapy is advocated for the global control and elimination of schistosomiasis. Despite the well known short-term benefits of treating patients for schistosomiasis, the impact of mass drug administration (MDA) campaigns to control the disease in the long term remains unresolved. RECENT FINDINGS Many studies have advocated the success of MDA programs in order to attract donor funds for elimination efforts but such successes are often short-lived given the drug does not alter the life cycle of the organism or prevent reinfection. Within a matter of months to years after halting treatment, the prevalence, intensity of infection and morbidity of disease return to baseline levels. Other mitigating factors contribute to the failings of MDA campaigns namely: poverty, poor drug coverage, poor drug compliance, and, in the case of Asiatic schistosomiasis, zoonotic transmission. Genetic and innate and acquired immunologic mechanisms complicate the epidemiologic picture of schistosomiasis globally, and may contribute indirectly to MDA shortcomings. The possibility of drug resistance is an ever present concern because of the sole reliance on one drug, praziquantel. SUMMARY Preventive chemotherapy is advocated for the global control and elimination of schistosomiasis. The short-term benefits of MDA campaigns are well documented but the long-term benefits are questionable.
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Wu X, Ren J, Gao Z, Xu Y, Xie H, Li T, Cheng Y, Hu F, Liu H, Gong Z, Liang J, Shen J, Liu Z, Wu F, Sun X, Niu Z, Ning A. Plasma D-dimer Can Effectively Predict the Prospective Occurrence of Ascites in Advanced Schistosomiasis Japonica Patients. THE KOREAN JOURNAL OF PARASITOLOGY 2017; 55:167-174. [PMID: 28506039 PMCID: PMC5450959 DOI: 10.3347/kjp.2017.55.2.167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 12/29/2022]
Abstract
China still has more than 30,000 patients of advanced schistosomiasis while new cases being reported consistently. D-dimer is a fibrin degradation product. As ascites being the dominating symptom in advanced schistosomiasis, the present study aimed to explore a prediction model of ascites with D-dimer and other clinical easy-achievable indicators. A case-control study nested in a prospective cohort was conducted in schistosomiasis-endemic area of southern China. A total of 291 patients of advanced schistosomiasis were first investigated in 2013 and further followed in 2014. Information on clinical history, physical examination, and abdominal ultrasonography, including the symptom of ascites was repeatedly collected. Result showed 44 patients having ascites. Most of the patients’ ascites were confined in the kidney area with median area of 20 mm2. The level of plasma D-dimer and pertinent liver function indicators were measured at the initial investigation in 2013. Compared with those without ascites, cases with ascites had significantly higher levels of D-dimer (0.71±2.44 μg/L vs 0.48±2.12 μg/L, P=0.005), as well ALB (44.5 vs 46.2, g/L) and Type IV collagen (50.04 vs 44.50 μg/L). Receiver operating characteristic curve analyses indicated a moderate predictive value of D-dimer by its own area under curve (AUC) of 0.64 (95% CI: 0.54–0.73) and the cutoff value as 0.81 μg/L. Dichotomized by the cutoff level, D-dimer along with other categorical variables generated a prediction model with AUC of 0.76 (95% CI: 0.68–0.89). Risks of patients with specific characteristics in the prediction model were summarized. Our study suggests that the plasma D-dimer level is a reliable predictor for incident ascites in advanced schistosomiasis japonica patients.
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Affiliation(s)
- Xiaoying Wu
- School of Public Health, Fudan University, Shanghai, China
| | - Jianwei Ren
- Health Department of Guard Bureau of General Office of the Communist Party of China, Beijing, P. R. China
| | - Zulu Gao
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Yun Xu
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Huiqun Xie
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Tingfang Li
- Schistosomiasis Control Station of Yugan County, Shangrao, P. R. China
| | - Yanhua Cheng
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Fei Hu
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Hongyun Liu
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Zhihong Gong
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
| | - Jinyi Liang
- Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Guangzhou, P. R. China.,Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, P. R. China
| | - Jia Shen
- Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Guangzhou, P. R. China.,Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, P. R. China
| | - Zhen Liu
- Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Guangzhou, P. R. China.,Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, P. R. China
| | - Feng Wu
- Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Guangzhou, P. R. China.,Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, P. R. China
| | - Xi Sun
- Key Laboratory of Tropical Diseases and Control of the Ministry of Education, Guangzhou, P. R. China.,Department of Parasitology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, P. R. China
| | - Zhongzheng Niu
- School of Community and Global Health, Claremont Graduate University, Claremont, California, USA
| | - An Ning
- Jiangxi Provincial Institute of Parasitic Diseases, Nanchang, P. R. China
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Tendler M, Almeida M, Simpson A. Development of the Brazilian Anti Schistosomiasis Vaccine Based on the Recombinant Fatty Acid Binding Protein Sm14 Plus GLA-SE Adjuvant. Front Immunol 2015; 6:218. [PMID: 26029206 PMCID: PMC4429245 DOI: 10.3389/fimmu.2015.00218] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/21/2015] [Indexed: 11/13/2022] Open
Abstract
Data herein reported and discussed refer to vaccination with the recombinant fatty acid binding protein (FABP) family member of the schistosomes, called Sm14. This antigen was discovered and developed under a Brazilian platform led by the Oswaldo Cruz Foundation, from the Health Ministry in Brazil, and was assessed for safety and immunogenicity in healthy volunteers. This paper reviews past and recent outcomes of developmental phases of the Sm14-based anti schistosomiasis vaccine addressed to, ultimately, impact transmission of the second most prevalent parasitic endemic disease worldwide.
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Affiliation(s)
- Miriam Tendler
- Oswaldo Cruz Institute, Oswaldo Cruz Foundation , Rio de Janeiro, Rio de Janeiro , Brazil
| | - Marilia Almeida
- Oswaldo Cruz Institute, Oswaldo Cruz Foundation , Rio de Janeiro, Rio de Janeiro , Brazil
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Amsalu G, Mekonnen Z, Erko B. A new focus of schistosomiasis mansoni in Hayk town, northeastern Ethiopia. BMC Res Notes 2015; 8:22. [PMID: 25643852 PMCID: PMC4318522 DOI: 10.1186/s13104-014-0965-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 12/30/2014] [Indexed: 11/13/2022] Open
Abstract
Background The endemicity of human schistosomiasis has long been established in Ethiopia, and new foci have also been continuously reported. The objective of this study was to determine the transmission and magnitude of schistosomiasis in Hayk area, northeastern Ethiopia. Methods A cross sectional parasitological survey involving 384 school children was conducted for intestinal schistosomiasis between January and March 2010 in two primary schools in Hayk area, northeastern Ethiopia. The stool samples were processed for microscopic examination using Kato-Katz technique. Malacological survey and observation on human water contact activities were also carried out. Snails were checked for schistosome infection by shedding and lab-bred mice were exposed to the cercariae shed from Biomphalaria pfeifferi en masse. Adult Schistosoma mansoni worms were harvested from the mice after 45 days of exposure to the schistosome cercariae. Results The overall prevalence and intensity of intestinal schistosomiasis among school children in Hayk Number 1 and Hayk Number 2 Primary Schools was found to be 45% and 161 epg, respectively. The prevalence of infection had relationship with age and sex. Males were more infected than females. Children in the age group 15-19 years had the highest infection rate, followed by 10-14 and 5-9 years age group. Schistosome infection in Biomphalaria pfeifferi was 3.2%. Schistosome infection was also established in laboratory-bred mice and adult Schistosoma mansoni worms were harvested. Conclusion The observed intestinal schistosomiasis with prevalence of 45% among young children, collection of schistosome infected Biomphalaria pfeifferi, and the establishment of lab infection in mice showed that transmission of intestinal schistosomiasis is taking place in the area. Preventive chemotherapy with praziquantel should be immediately put in place to reduce morbidity and interrupt transmission of schistosomiasis in the area.
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Affiliation(s)
| | - Zeleke Mekonnen
- Department of Medical Laboratory Sciences and Pathology,College of Public Health and Medical Sciences, Jimma University, Jimma, Ethiopia.
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Gordon CA, Acosta LP, Gobert GN, Olveda RM, Ross AG, Williams GM, Gray DJ, Harn D, Li Y, McManus DP. Real-time PCR demonstrates high prevalence of Schistosoma japonicum in the Philippines: implications for surveillance and control. PLoS Negl Trop Dis 2015; 9:e0003483. [PMID: 25606851 PMCID: PMC4301913 DOI: 10.1371/journal.pntd.0003483] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 12/16/2014] [Indexed: 11/17/2022] Open
Abstract
Background The Philippines has a population of approximately 103 million people, of which 6.7 million live in schistosomiasis-endemic areas with 1.8 million people being at risk of infection with Schistosoma japonicum. Although the country-wide prevalence of schistosomiasis japonica in the Philippines is relatively low, the prevalence of schistosomiasis can be high, approaching 65% in some endemic areas. Of the currently available microscopy-based diagnostic techniques for detecting schistosome infections in the Philippines and elsewhere, most exhibit varying diagnostic performances, with the Kato-Katz (KK) method having particularly poor sensitivity for detecting low intensity infections. This suggests that the actual prevalence of schistosomiasis japonica may be much higher than previous reports have indicated. Methodology/Principal Findings Six barangay (villages) were selected to determine the prevalence of S. japonicum in humans in the municipality of Palapag, Northern Samar. Fecal samples were collected from 560 humans and examined by the KK method and a validated real-time PCR (qPCR) assay. A high S. japonicum prevalence (90.2%) was revealed using qPCR whereas the KK method indicated a lower prevalence (22.9%). The geometric mean eggs per gram (GMEPG) determined by the qPCR was 36.5 and 11.5 by the KK. These results, particularly those obtained by the qPCR, indicate that the prevalence of schistosomiasis in this region of the Philippines is much higher than historically reported. Conclusions/Significance Despite being more expensive, qPCR can complement the KK procedure, particularly for surveillance and monitoring of areas where extensive schistosomiasis control has led to low prevalence and intensity infections and where schistosomiasis elimination is on the horizon, as for example in southern China. Schistosomiasis is caused by infection with trematode blood flukes of the genus Schistosoma. Schistosoma japonicum is the causative agent of schistosomiasis in the Philippines, China and parts of Indonesia. In the Philippines, 6.7 million people live in endemic areas and 1.8 million are at risk of infection whereas concerted control efforts over the past 50 years in China have reduced the number of infected individuals considerably. Currently used microscopic techniques for diagnosis, notably the Kato-Katz (KK) technique, lack sensitivity in areas with low intensity schistosome infections. We have used a molecular diagnostic approach (qPCR), to assess the prevalence of S. japonicum in humans from six barangays in Northern Samar, the Philippines. The qPCR performed considerably better than the KK as a diagnostic procedure and could be an important tool in the future for surveillance and monitoring of areas where extensive schistosomiasis control has led to low prevalence and intensity infections and where schistosomiasis elimination is possible.
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Affiliation(s)
- Catherine. A. Gordon
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Discipline of Epidemiology and Biostatistics, School of Population Health, University of Queensland, Brisbane, Australia
- * E-mail: (CAG); (DPM)
| | - Luz P. Acosta
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Geoffrey N. Gobert
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Remigio M. Olveda
- Department of Immunology, Research Institute of Tropical Medicine, Manila, Philippines
| | - Allen G. Ross
- Griffith Health Institute, Griffith University, Queensland, Australia
| | - Gail M. Williams
- Discipline of Epidemiology and Biostatistics, School of Population Health, University of Queensland, Brisbane, Australia
| | - Darren J. Gray
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- Discipline of Epidemiology and Biostatistics, School of Population Health, University of Queensland, Brisbane, Australia
- Research School of Population Health, College of Medicine, Biology and Environment, the Australian National University, Canberra, Australia
| | - Donald Harn
- University of Georgia, College of Veterinary Medicine, Athens, Georgia, United States of America
| | - Yuesheng Li
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Donald P. McManus
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Australia
- * E-mail: (CAG); (DPM)
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Wang ML, Cao YM, Luo EJ, Zhang Y, Guo YJ. Pre-existing Schistosoma japonicum infection alters the immune response to Plasmodium berghei infection in C57BL/6 mice. Malar J 2013; 12:322. [PMID: 24034228 PMCID: PMC3848616 DOI: 10.1186/1475-2875-12-322] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 08/18/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Since helminths and malaria parasites are often co-endemic, it is important to clarify the immunoregulatory mechanism that occurs during the process of co-infection. A previous study confirmed that dendritic cells (DCs) are involved in the establishment and regulation of the T-cell-mediated immune response to malaria infection. In the current study, distinct response profiles for splenic DCs and regulatory T cell (Treg) responses were assessed to evaluate the effects of a pre-existing Schistosoma japonicum infection on malaria infection. METHODS Malaria parasitaemia, survival rate, brain histopathology and clinical experimental cerebral malaria (ECM) were assessed in both Plasmodium berghei ANKA-mono-infected and S. japonicum-P. berghei ANKA-co-infected mice. Cell surface/intracellular staining and flow cytometry were used to analyse the level of splenic DC subpopulations, toll-like receptors (TLRs), DC surface molecules, Tregs (CD4⁺CD25⁺Foxp3⁺), IFN-γ/IL-10-secreting Tregs, and IFN-γ⁺/IL-10⁺-Foxp3⁻CD4⁺ T cells. IFN-γ, IL-4, IL-5, IL-10 and IL-13 levels were determined in splenocyte supernatants using enzyme-linked immunosorbent assay (ELISA). RESULTS The co-infected mice had significantly higher malaria parasitaemia, compared with the mono-infected mice, on days 2, 3, 7 and 8 after P. berghei ANKA infection. Mono-infected mice had a slightly lower survival rate, while clinical ECM symptoms, and brain pathology, were significantly more severe during the period of susceptibility to ECM. On days 5 and 8 post P. berghei ANKA infection, co-infected mice had significantly lower levels of CD11c⁺CD11b⁺, CD11c⁺CD45R/B220⁺, CD11c⁺TLR4⁺, CD11c⁺TLR9⁺, CD11c⁺MHCII⁺, CD11c⁺CD86⁺, IFN-γ-secreting Tregs, and IFN-γ⁺Foxp3⁻CD4⁺ T cells in single-cell suspensions of splenocytes when compared with P. berghei ANKA-mono-infected mice. Co-infected mice also had significantly lower levels of IFN-γ and higher levels of IL-4, IL-5, and IL-13 in splenocyte supernatants compared to mono-infected mice. There were no differences in the levels of IL-10-secreting Tregs or IL-10⁺Foxp3⁻CD4⁺ T cells between co-infected and mono-infected mice. CONCLUSIONS A Tregs-associated Th2 response plays an important role in protecting against ECM pathology. Pre-existing S. japonicum infection suppressed TLR ligand-induced DC maturation and had an anti-inflammatory effect during malaria infection not only by virtue of its ability to induce Th2 responses, but also by directly suppressing the ability of DC to produce pro-inflammatory mediators.
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Affiliation(s)
- Mei-lian Wang
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, No. 92 Beier Road, Heping District, Shenyang 110001, China
| | - Ya-ming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, No. 92 Beier Road, Heping District, Shenyang 110001, China
| | - En-jie Luo
- Department of Microbiology and Parasitology, College of Basic Medical Sciences, China Medical University, No. 92 Beier Road, Heping District, Shenyang 110001, China
| | - Ying Zhang
- Department of Sonography, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110004, China
| | - Ya-jun Guo
- Department of Sonography, Shengjing Hospital of China Medical University, No. 36 Sanhao Street, Heping District, Shenyang 110004, China
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Vandemark LM, Jia TW, Zhou XN. Social science implications for control of helminth infections in Southeast Asia. ADVANCES IN PARASITOLOGY 2010; 73:137-70. [PMID: 20627142 DOI: 10.1016/s0065-308x(10)73006-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Social science perspectives can inform helminth disease control in Southeast Asia. The social science literature offers theoretical and conceptual models; research methods; recommendations for training and capacity building, health education and health care professional training; and practice guidelines, including implementation of evidence-based interventions. Priority themes include poverty, gender differences, health inequities and access to social resources. Implications for helminth control include broadening disease monitoring and surveillance to include social and economic variables and subjective measures of well-being; training for health professionals and researchers in the social determinants of health; and application of social science models, specifically the expanded 'Chronic Care Model', to the planning and evaluation of interventions. The chapter posits that helminth diseases meet the World Health Organization's expanded definition of chronic conditions, and that integrated delivery of multiple interventions is needed to address the full range of risks and outcomes due to helminth infection.
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Affiliation(s)
- Lisa M Vandemark
- College of Health and Human Services, George Mason University, USA
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12
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Carlton EJ, Hsiang M, Zhang Y, Johnson S, Hubbard A, Spear RC. The impact of Schistosoma japonicum infection and treatment on ultrasound-detectable morbidity: a five-year cohort study in Southwest China. PLoS Negl Trop Dis 2010; 4:e685. [PMID: 20502515 PMCID: PMC2872638 DOI: 10.1371/journal.pntd.0000685] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Accepted: 03/26/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Ultrasonography allows for non-invasive examination of the liver and spleen and can further our understanding of schistosomiasis morbidity. METHODOLOGY/PRINCIPAL FINDINGS We followed 578 people in Southwest China for up to five years. Participants were tested for Schistosoma japonicum infection in stool and seven standard measures of the liver and spleen were obtained using ultrasound to evaluate the relationship between schistosomiasis infection and ultrasound-detectable pathology, and the impact of targeted treatment on morbidity. Parenchymal fibrosis, a network pattern of the liver unique to S. japonicum, was associated with infection at the time of ultrasound (OR 1.40, 95% CI: 1.03-1.90) and infection intensity (test for trend, p = 0.002), adjusting for age, sex and year, and more strongly associated with prior infection status and intensity (adjusted OR 1.84, 95% CI: 1.30-2.60; test for trend: p<0.001 respectively), despite prompt treatment of infections. While declines in parenchymal fibrosis over time were statistically significant, only 28% of individuals with severe parenchymal fibrosis (grades 2 or 3) at enrollment reversed to normal or grade 1 within five years. Other liver abnormalities were less consistently associated with S. japonicum infection. CONCLUSIONS/SIGNIFICANCE Parenchymal fibrosis is an appropriate measure of S. japonicum morbidity and can document reductions in disease following control efforts. Other ultrasound measures may have limited epidemiological value in regions with similar infection levels. Because severe fibrosis may not reverse quickly following treatment, efforts to reduce exposure to S. japonicum should be considered in combination with treatment to prevent schistosomiasis morbidity.
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Affiliation(s)
- Elizabeth J Carlton
- Department of Environmental Health Sciences, University of California, Berkeley, California, United States of America.
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Yanagisawa S, Yuasa T, Tanaka T. Clinical diagnosis of Schistosoma japonicum infection complicating infective endocarditis and liver cirrhosis. Intern Med 2010; 49:1001-5. [PMID: 20519816 DOI: 10.2169/internalmedicine.49.3121] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human infection with the parasite Schistosoma japonicum is rarely seen in Japan. Infection with the parasite is currently known to be endemic in China and South-east Asia, and chronic infection leads to the development of liver fibrosis, calcification and portal hypertension. We report a case of Schistosoma japonicum infection complicating infective endocarditis and liver cirrhosis. The non-invasive imaging findings and serological test were helpful to diagnose the infection with the parasite. Since Schistosoma japonicum infection is extremely rare in Japan, the diagnosis and evaluation of the patient's condition was delayed.
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Sörén K, Monrad J, Johansen MV, Lindberg R. Persistent immune responses in late infection and after treatment in experimental Schistosoma bovis infections in goats. Res Vet Sci 2008; 86:472-8. [PMID: 19027127 DOI: 10.1016/j.rvsc.2008.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Revised: 09/10/2008] [Accepted: 10/13/2008] [Indexed: 11/28/2022]
Abstract
This study explored host immune responses and their possible relationship to the anti-fecundity phenomenon in Schistosoma bovis-infected goats. The design comprised a primary infection with or without treatment at week (wk) 13, and with or without challenge at wk 36. Necropsy was performed at 36 or 52wk. Serum levels of anti-egg IgG, and anti-worm IgG and IgM, were measured by ELISA. In chronic infection, anti-worm antibodies stayed high, reflecting persisting worm burdens, whereas anti-egg IgG remained high despite minimized egg excretion. After treatment, anti-worm IgM and anti-egg IgG were minimized, but anti-worm IgG remained above the values of the uninfected controls. Histopathology showed lowered numbers of perioval granulomas in chronic infection and resolution of liver fibrosis with time, but intestinal lymphoplasmacytic perivasculitis and hepatic eosinophilic infiltrates were maintained at wk 52. Significant splenic plasmacytosis persisted after treatment. The results indicated that persistent immune responses, in chronically infected and in treated goats, may explain sustained worm fecundity depression at challenge infection.
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Affiliation(s)
- K Sörén
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, P.O. Box 7028, SE-750 07 Uppsala, Sweden.
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15
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Ezeamama AE, McGarvey ST, Acosta LP, Zierler S, Manalo DL, Wu HW, Kurtis JD, Mor V, Olveda RM, Friedman JF. The synergistic effect of concomitant schistosomiasis, hookworm, and trichuris infections on children's anemia burden. PLoS Negl Trop Dis 2008; 2:e245. [PMID: 18523547 PMCID: PMC2390851 DOI: 10.1371/journal.pntd.0000245] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2007] [Accepted: 05/08/2008] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE To estimate the degree of synergism between helminth species in their combined effects on anemia. METHODS Quantitative egg counts using the Kato-Katz method were determined for Ascaris lumbricoides, hookworm, Trichuris trichiura, and Schistosoma japonicum in 507 school-age children from helminth-endemic villages in The Philippines. Infection intensity was defined in three categories: uninfected, low, or moderate/high (M+). Anemia was defined as hemoglobin <11 g/dL. Logistic regression models were used to estimate odds ratios (OR), 95% confidence intervals (CI), and synergy index for pairs of concurrent infections. RESULTS M+ co-infection of hookworm and S. japonicum (OR = 13.2, 95% CI: 3.82-45.5) and of hookworm and T. trichiura (OR = 5.34, 95% CI: 1.76-16.2) were associated with higher odds of anemia relative to children without respective M+ co-infections. For co-infections of hookworm and S. japonicum and of T. trichiura and hookworm, the estimated indices of synergy were 2.9 (95% CI: 1.1-4.6) and 1.4 (95% CI: 0.9-2.0), respectively. CONCLUSION Co-infections of hookworm and either S. japonicum or T. trichiura were associated with higher levels of anemia than would be expected if the effects of these species had only independent effects on anemia. This suggests that integrated anti-helminthic treatment programs with simultaneous deworming for S. japonicum and some geohelminths could yield a greater than additive benefit for reducing anemia in helminth-endemic regions.
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Affiliation(s)
- Amara E Ezeamama
- Department of Community Health and International Health Institute, Brown University Providence, Rhode Island, USA.
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Finkelstein JL, Schleinitz MD, Carabin H, McGarvey ST. Decision-model estimation of the age-specific disability weight for schistosomiasis japonica: a systematic review of the literature. PLoS Negl Trop Dis 2008; 2:e158. [PMID: 18320018 PMCID: PMC2254314 DOI: 10.1371/journal.pntd.0000158] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2007] [Accepted: 12/04/2007] [Indexed: 11/30/2022] Open
Abstract
Schistosomiasis is among the most prevalent parasitic infections worldwide. However, current Global Burden of Disease (GBD) disability-adjusted life year estimates indicate that its population-level impact is negligible. Recent studies suggest that GBD methodologies may significantly underestimate the burden of parasitic diseases, including schistosomiasis. Furthermore, strain-specific disability weights have not been established for schistosomiasis, and the magnitude of human disease burden due to Schistosoma japonicum remains controversial. We used a decision model to quantify an alternative disability weight estimate of the burden of human disease due to S. japonicum. We reviewed S. japonicum morbidity data, and constructed decision trees for all infected persons and two age-specific strata, <15 years (y) and ≥15 y. We conducted stochastic and probabilistic sensitivity analyses for each model. Infection with S. japonicum was associated with an average disability weight of 0.132, with age-specific disability weights of 0.098 (<15 y) and 0.186 (≥15 y). Re-estimated disability weights were seven to 46 times greater than current GBD measures; no simulations produced disability weight estimates lower than 0.009. Nutritional morbidities had the greatest contribution to the S. japonicum disability weight in the <15 y model, whereas major organ pathologies were the most critical variables in the older age group. GBD disability weights for schistosomiasis urgently need to be revised, and species-specific disability weights should be established. Even a marginal increase in current estimates would result in a substantial rise in the estimated global burden of schistosomiasis, and have considerable implications for public health prioritization and resource allocation for schistosomiasis research, monitoring, and control. Schistosomiasis is a parasitic infection caused by a flatworm that disproportionately affects the world's poorest populations. Schistosomiasis is one of the most common infections worldwide, affecting over 207 million people in 76 countries. Current international estimates indicate that schistosomiasis has a minimal impact at the population level. This has contributed to its low prioritization in global health and subsequent resource allocation for disease control. However, recent studies indicate that these measures underestimate the extent of neglected tropical diseases, including schistosomiasis. Despite World Health Organization recommendations, the burden of schistosomiasis has not been re-examined in over a decade, and there are no established estimates for different types of schistosomiasis. The impact of symptoms associated with the Asian strain, Schistosoma japonicum, remains controversial. This study was conducted to provide an alternate measure of the burden of S. japonicum. We reviewed the literature and calculated a summary estimate for S. japonicum which was seven to 46 times greater than current measures for schistosomiasis. Findings suggest that current measures severely underestimate the extent of schistosomiasis, and urgently need to be revised. Further research is needed to examine the burden of schistosomiasis and other forgotten tropical diseases affecting the world's poorest people in endemic countries.
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Affiliation(s)
- Julia L Finkelstein
- Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts, USA.
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Fernandez TJ, Tarafder MR, Balolong E, Joseph L, Willingham AL, Bélisle P, Webster JP, Olveda RM, McGarvey ST, Carabin H. Prevalence of Schistosoma japonicum infection among animals in fifty villages of Samar province, the Philippines. Vector Borne Zoonotic Dis 2007; 7:147-55. [PMID: 17627431 DOI: 10.1089/vbz.2006.0565] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the Philippines, there is a need to understand the contribution of different domestic and wild animals in transmitting Schistosoma japonicum infection to humans better. The current study describes variation in animal S. japonicum prevalence across 50 endemic villages of Samar Province, the Philippines. A total of 50 villages were selected, 25 with predominantly rain-fed farms and 25 with some irrigation system. At least 35 cats, dogs, pigs, and water buffaloes each were randomly selected and 30 rat traps were set in each village. Fecal samples were collected for up to three consecutive days for each species. The Danish Bilharziasis Laboratory method (DBL method) was used to determine S. japonicum infection status. A hierarchical logistic regression model with clustering by village and with adjustment for measurement error of the DBL method was used to estimate the prevalence of infection per village and species. Stool samples were collected from 23.4% (1189), 28.6% (1274), 36.3% (1899), and 49.4% (873) of the censused dogs, cats, pigs, and water buffaloes, respectively, and from 663 rats. The adjusted prevalence of S. japonicum infection varied greatly across villages ranging from 1.6% (95% Bayesian Credible Interval: 0.1%-10.2%) to 86.3% (65.9%-97.8%) for dogs, from 0.1% (0%-2.1%) to 21.7% (4.7%-51.2%) for cats, from 0.01% (0.0%%-1.0%) to 18.4% (7.1%-34.7%) for pigs, from less than 0.1% (0.0%-1.2%) to 72.5% (46.0%-97.4%) for water buffaloes, and from 0.7% (0.0%-9.0%) to 95.4% (77.2%-99.9%) for rats. This is the most comprehensive study of animal S. japonicum infection conducted to date. Our results show that, unlike what has been reported in China, very few water buffaloes were infected whereas rats and dogs show high prevalence proportions of infection. This, combined with significant village-to-village variation in prevalence of S. japonicum infection, suggest possible different transmission dynamics of the infection in the Province of Samar in the Philippines and China.
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Affiliation(s)
- T J Fernandez
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Fitzpatrick JM, Hirai Y, Hirai H, Hoffmann KF. Schistosome egg production is dependent upon the activities of two developmentally regulated tyrosinases. FASEB J 2006; 21:823-35. [PMID: 17167065 DOI: 10.1096/fj.06-7314com] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Egg production is responsible for life cycle progression and host immunopathology during schistosomiasis, with the associated parasite molecules being investigated as potential novel chemotherapeutic targets. Here, we characterize two Schistosoma mansoni products, tyrosinase 1 and tyrosinase 2 (SmTYR1/SmTYR2) and show that their diphenol oxidase enzyme activities are critical for eggshell formation and production. The genes encoding these bifunctional enzymes (monophenol and diphenol oxidases) result from a duplication event that likely occurred before speciation and exist in the parasite's genome as multiple copies, which are linked and localized to chromosomes 4 and W. SmTYR1/SmTYR2 transcription and diphenol oxidase action are developmentally regulated with most enzyme activity localized to the eggshell-producing cells contained within the vitellaria of adult female worms. Importantly, kojic-acid mediated inhibition (IC50=0.5 microM) of SmTYR1/SmTYR2's diphenol oxidase activity during in vitro culture of sexually mature adult worms resulted in a significant decrease in the production of phenotypically normal eggs. Therefore our data suggest that SmTYR1/2 inhibition represents a novel and potentially effective strategy for combating schistosomiasis and furthermore, it may point to new methods for combinatorial control of immunopathology and egg transmission during platyhelminth infection.
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Leenstra T, Coutinho HM, Acosta LP, Langdon GC, Su L, Olveda RM, McGarvey ST, Kurtis JD, Friedman JF. Schistosoma japonicum reinfection after praziquantel treatment causes anemia associated with inflammation. Infect Immun 2006; 74:6398-407. [PMID: 16923790 PMCID: PMC1695508 DOI: 10.1128/iai.00757-06] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
There is a relationship between schistosomiasis and anemia, although the magnitude and exact mechanisms involved are unclear. In a cohort of 580 Schistosoma japonicum-infected 7- to 30-year-old patients from Leyte, The Philippines, we evaluated the impact of reinfection with S. japonicum after treatment with praziquantel on the mean hemoglobin level, iron-deficiency (IDA) and non-iron-deficiency anemia (NIDA), and inflammatory markers. All participants were treated at baseline and followed up every 3 months for a total of 18 months. At each follow-up, participants provided stools to quantify reinfection and venous blood samples for hemograms and measures of iron status and inflammation. After 18 months, reinfection with S. japonicum was associated with a lower mean hemoglobin level (-0.39 g/dl; 95% confidence interval [95% CI], -0.63 to -0.16) and 1.70 (95% CI, 1.10 to 2.61) times higher odds of all-cause anemia than those without reinfection. Reinfection was associated with IDA for high reinfection intensities only. Conversely, reinfection was associated with NIDA for all infection intensities. Reinfection was associated with serum interleukin-6 responses (P<0.01), and these responses were associated with NIDA (P=0.019) but not with IDA (P=0.29). Our results provide strong evidence for the causal relationship between S. japonicum infection and anemia. Rapidly reinfected individuals did not have the positive treatment effect on hemoglobin seen in nonreinfected individuals. The principle mechanism involved in S. japonicum-associated anemia is that of proinflammatory cytokine-mediated anemia, with iron deficiency playing a role in high-intensity infections. Based on the proposed mechanism, anemia is unlikely to be ameliorated by iron therapy alone.
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Affiliation(s)
- Tjalling Leenstra
- Center for International Health Research, Lifespan Hospitals, and Department of Pediatrics, Brown University Medical School, 55 Claverick Street, Suite 102, Providence, RI 02903, USA.
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Olds GR. New insights into the observed age-specific resistance to reinfection with Schistosoma japonicum. Clin Infect Dis 2006; 42:1699-701. [PMID: 16705574 DOI: 10.1086/504331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Accepted: 03/01/2006] [Indexed: 11/03/2022] Open
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Tarafder MR, Balolong E, Carabin H, Bélisle P, Tallo V, Joseph L, Alday P, Gonzales RO, Riley S, Olveda R, McGarvey ST. A cross-sectional study of the prevalence of intensity of infection with Schistosoma japonicum in 50 irrigated and rain-fed villages in Samar Province, the Philippines. BMC Public Health 2006; 6:61. [PMID: 16526960 PMCID: PMC1421391 DOI: 10.1186/1471-2458-6-61] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Accepted: 03/09/2006] [Indexed: 11/12/2022] Open
Abstract
Background Few studies have described heterogeneity in Schistosoma japonicum infection intensity, and none were done in Philippines. The purpose of this report is to describe the village-to-village variation in the prevalence of two levels of infection intensity across 50 villages of Samar Province, the Philippines. Methods This cross-sectional study was conducted in 25 rain-fed and 25 irrigated villages endemic for S. japonicum between August 2003 and November 2004. Villages were selected based on irrigation and farming criteria. A maximum of 35 eligible households were selected per village. Each participant was asked to provide stool samples on three consecutive days. All those who provided at least one stool sample were included in the analysis. A Bayesian three category outcome hierarchical cumulative logit regression model with adjustment for age, sex, occupation and measurement error of the Kato-Katz technique was used for analysis. Results A total of 1427 households and 6917 individuals agreed to participate in the study. A total of 5624 (81.3%) participants provided at least one stool sample. The prevalences of those lightly and at least moderately infected varied from 0% (95% Bayesian credible interval (BCI): 0%–3.1%) to 45.2% (95% BCI: 36.5%–53.9%) and 0% to 23.0% (95% BCI: 16.4%–31.2%) from village-to-village, respectively. Using the 0–7 year old group as a reference category, the highest odds ratio (OR) among males and females were that of being aged 17–40-year old (OR = 8.76; 95% BCI: 6.03–12.47) and 11–16-year old (OR = 8.59; 95% BCI: 4.74–14.28), respectively. People who did not work on a rice farm had a lower prevalence of infection than those working full time on a rice farm. The OR for irrigated villages compared to rain-fed villages was 1.41 (95% BCI: 0.50–3.21). Discussion We found very important village-to-village variation in prevalence of infection intensity. This variation is probably due to village-level variables other than that explained by a crude classification of villages into the irrigated and non-irrigated categories. We are planning to capture this spatial heterogeneity by updating our initial transmission dynamics model with the data reported here combined with 1-year post-treatment follow-up of study participants.
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Affiliation(s)
- Mushfiqur R Tarafder
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma, USA
| | - Ernesto Balolong
- Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippines
| | - Hélène Carabin
- Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma, USA
| | - Patrick Bélisle
- Division of Clinical Epidemiology, Montreal General Hospital, McGill University Health Center, Montreal, Quebec, Canada
| | - Veronica Tallo
- Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippines
| | - Lawrence Joseph
- Department of Epidemiology and Biostatistics, Faculty of Medicine, McGill University, Montréal, Québec, Canada
| | - Portia Alday
- Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippines
| | | | - Steven Riley
- Department of Community Medicine, Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Remigio Olveda
- Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippines
| | - Stephen T McGarvey
- International Health Institute, Brown University, Providence, Rhode Island, USA
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Coutinho HM, Acosta LP, McGarvey ST, Jarilla B, Jiz M, Pablo A, Su L, Manalo DL, Olveda RM, Kurtis JD, Friedman JF. Nutritional status improves after treatment of schistosoma japonicum-infected children and adolescents. J Nutr 2006; 136:183-8. [PMID: 16365080 DOI: 10.1093/jn/136.1.183] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Studies addressing the relation between chronic schistosomiasis japonica and nutritional status are limited. We conducted a longitudinal treatment-reinfection study in Leyte, the Philippines, among 477 Schistosoma japonicum-infected subjects aged 7-20 y, to evaluate changes in nutritional status after treatment with praziquantel. Stool, Tanner stage, anthropometric indices, and hemoglobin (Hb) were evaluated at baseline, 4 wk post-treatment, and every 3 mo for 18 mo. Height-for-age Z-score (HAZ) and BMI Z-score (BMIZ) were calculated. Change scores relative to baseline were created for all outcome measures. Multilevel repeated-measures analyses were used to adjust for socioeconomic status, sex, either pubertal status or age, and household-level clustering. Z-scores improved modestly but significantly over time. BMIZ in children wasted at baseline improved the most [0.41 (0.26-0.56) Z-score unit] and HAZ improved only in children stunted at baseline [0.17 (0.l2-0.21) Z-score unit]. Hb improvement peaked at 15 mo and occurred only in subjects that were anemic at baseline [peak improvement: 8.3 (6.0-10.6) g/L] and in males [peak improvement 4.7 (2.9-6.6) g/L]. Reinfection, evaluated as egg count over time and egg count 3 mo earlier to assess a delay in effect, was inversely associated with improvement in Hb (P = 0.06 and 0.004, respectively). High-intensity reinfection at 18 mo was associated with significantly less absolute growth from baseline compared with lower-intensity and no reinfection. Based on the peak Hb improvement at 15 mo post-treatment, annual treatment intervals are recommended to reduce schistosomiasis-associated nutritional morbidity.
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Affiliation(s)
- Hannah M Coutinho
- Center for International Health Research, Brown University Medical School, Providence, RI, USA.
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23
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Bergquist NR, Leonardo LR, Mitchell GF. Vaccine-linked chemotherapy: can schistosomiasis control benefit from an integrated approach? Trends Parasitol 2005; 21:112-7. [PMID: 15734657 DOI: 10.1016/j.pt.2005.01.001] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The present strong emphasis on gross organ pathology (liver, kidneys, bladder) in schistosomiasis needs to be replaced with a more balanced view of the disease that also takes into account systemic symptoms that are less easy to assess, such as retarded growth, cognitive development and the effect of continuing low-level blood loss. Access to better estimates of disease burdens, morbidity and mortality is delivering results that bring into question the wisdom of downgrading the impact of the disease. In this scenario, the simplistic approach of exclusive drug treatment might not be sufficient and, in the worst-case scenario, might even exacerbate pathology. To meet this challenge, the repositioning of vaccines within the totality of disease control through the combined use of chemotherapy and vaccination is recommended as the basis for a novel, more-versatile approach to control. Studies on human correlate responses in endemic areas have opened the way to assess the protective value of specific antigens through the cytokine responses and antibodies they elicit. Moreover, vaccine formulations based on novel adjuvants could improve the final outcome through selective manipulation of the immune response. Thus, the tools of vaccine-linked chemotherapy are in principle already available and could shortly be put to the test in clinical trials.
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24
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Johansen MV, Ornbjerg N. PRENATAL SCHISTOSOMA JAPONICUM INFECTION IN PIGLETS: EFFECT OF REPEATED EXPOSURE OF THE DAMS ON TREATMENT EFFICACY AND SUSCEPTIBILITY TO CHALLENGE INFECTIONS. J Parasitol 2004; 90:392-6. [PMID: 15165065 DOI: 10.1645/ge-3262] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
This study elucidated the fate of prenatal infections in piglets born by dams repeatedly infected before and during pregnancy with Schistosoma japonicum. Independent variables included repeated infections of the dams and treatment or challenge infection (or both) of the prenatally exposed piglets. Dependant variables were worm counts, fecal and tissue egg counts, weight gain, and gross pathological observations. Fifteen female piglets (the dams) were included, of which 6 received repeated infections with S. japonicum during 6 mo. All dams were inseminated and 10 wk pregnant; 12 of the dams were infected with S. japonicum, of which 6 had been repeatedly infected. Three dams remained uninfected. Eight weeks after delivery, the prenatally exposed piglets (the offspring) were grouped, and 6 of the 12 groups were treated with praziquantel. Four weeks after treatment, 5 groups of piglets were infected with S. japonicum. Groups of piglets were killed either 12 or 22 wk after delivery. Repeated infections of the dam did not prevent establishment of a congenital infection in the pig fetuses. Piglets born with a congenital infection were not resistant to a S. japonicum challenge infection given 12 wk after birth. Neither did praziquantel effectively cure the piglets nor did treatment of the prenatally infected piglets prevent establishment of a challenge infection given 4 wk after treatment. Results of the present study indicate that prenatal exposure, independently of the dam's infection status, may change the host response to challenge infections and treatment after birth.
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Affiliation(s)
- Maria V Johansen
- Danish Bilharziasis Laboratory, Jaegersborg Alle 1 D, DK-2920 Charlottenlund, Denmark.
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25
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Abstract
Praziquantel (PZQ) is the safest of all anti-helminthics and now forms the backbone for all national control programs against schistosomiasis (Med. Res. Rev. 3 (1983) 147-200; Bull. WHO 57 (1979) 767-771; Wegner, D.H.G, Therapeutic Drugs (1991), Churchill Livingstone; Adv. Intern. Med. 32 (1987) 193-206; Drugs 42 (1991) 379-405; Pharmac. Ther. 68 (1995) 35-85; Ann. Intern. Med. 110 (1989) 290-296). Despite its lack of known toxicity, the drug was not tested on pregnant or lactating women prior to release. It is currently listed as Pregnancy Category B by the US FDA, which is a drug presumed safe based in animal studies. Unfortunately, this has been interpreted by most national control programs and WHO (1998) to exclude lactating and pregnant women from treatment. In fact, some experts advocate excluding adolescent girls from mass treatment campaigns over this issue. As a result, a large number of women living in endemic countries are currently left untreated or have treatment significantly delayed. A review of the current known toxicology of PZQ, combined with over two decades of clinical experience with this drug, suggest very low potential for adverse effects on either the mother or her unborn child. In contrast, significant animal and human data are presented in this review that suggest both the pregnant woman and her unborn fetus suffer morbid sequella from schistosomiasis. A double-blind placebo-controlled trial that could resolve this issue would require a very large and expensive study and in light of the above facts might not now be ethically appropriate. The author concludes that pregnant women should be treated with PZQ, that women of childbearing age should be included in all mass treatment programs and that lactating women are not systematically excluded from treatment.
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Affiliation(s)
- G Richard Olds
- Department of Medicine, Medical College of Wisconsin, 9200 W Wisconsin Ave, Suite 4100, Milwaukee, WI 53226, USA.
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26
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Affiliation(s)
- Allen G P Ross
- Medical University of the Americas, Charlestown, Nevis, West Indies
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27
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Abstract
Schistosomiasis is an important disease in many parts of the world and has affected the course of human history many times over. The parasitic infection is acquired during contact with infected water. A chronic inflammatory response to schistosome eggs, mediated by both cellular and humoral mechanisms, is the root of the pathology seen in schistosomiasis. Hepatosplenic disease results in intrahepatic presinusoidal portal hypertension. The resultant esophageal and gastric varices are an important cause of morbidity and mortality. Standard treatment guidelines for managing varices can be applied to patients with schistosomiasis. Coinfection with viral hepatitis results in liver disease that progresses more rapidly and is more difficult to treat. Intestinal schistosomiasis may be confused with other disease states and can be an important cause of morbidity, especially in heavily infected patients. Diagnosis relies on demonstration of schistosome eggs in feces or tissue. Praziquantel is the treatment of choice. The development of a vaccine for schistosomiasis is an important goal in the attempt to control this disease.
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Affiliation(s)
- T W Schafer
- Clinical Investigation Department (KCA), Naval Medical Center, San Diego, 34800 Bob Wilson Drive, Suite 5, San Diego, CA 92134-1005, USA
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28
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Ross AG, Sleigh AC, Li Y, Davis GM, Williams GM, Jiang Z, Feng Z, McManus DP. Schistosomiasis in the People's Republic of China: prospects and challenges for the 21st century. Clin Microbiol Rev 2001; 14:270-95. [PMID: 11292639 PMCID: PMC88974 DOI: 10.1128/cmr.14.2.270-295.2001] [Citation(s) in RCA: 238] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Schistosomiasis japonica is a serious communicable disease and a major disease risk for more than 30 million people living in the tropical and subtropical zones of China. Infection remains a major public health concern despite 45 years of intensive control efforts. It is estimated that 865,000 people and 100,250 bovines are today infected in the provinces where the disease is endemic, and its transmission continues. Unlike the other schistosome species known to infect humans, the oriental schistosome, Schistosoma japonicum, is a true zoonotic organism, with a range of mammalian reservoirs, making control efforts extremely difficult. Clinical features of schistosomiasis range from fever, headache, and lethargy to severe fibro-obstructive pathology leading to portal hypertension, ascites, and hepatosplenomegaly, which can cause premature death. Infected children are stunted and have cognitive defects impairing memory and learning ability. Current control programs are heavily based on community chemotherapy with a single dose of the drug praziquantel, but vaccines (for use in bovines and humans) in combination with other control strategies are needed to make elimination of the disease possible. In this article, we provide an overview of the biology, epidemiology, clinical features, and prospects for control of oriental schistosomiasis in the People's Republic of China.
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Affiliation(s)
- A G Ross
- Australian Centre for International and Tropical Health and Nutrition, The Queensland Institute of Medical Research, and the University of Queensland, Brisbane, Queensland 4029, Australia
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29
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Abstract
Schistosomiasis is a major parasitic disease, affecting nearly 200 million persons, worldwide. Major advances in our knowledge-in terms of pathogenesis, improved diagnosis, therapeutics (both drugs and strategies), and morbidity assessment-now make schistosomiasis a curable, often preventable disease. In contrast to most other illnesses, most schistosomiasis pathology appears to be reversible over time. For the future, several promising vaccine candidates are already in phase-I or phase-II testing. On the other hand, the range of this disease has been increasing, as water resources are developed in several newly industrialized countries and much of schistosomiasis in sub-Saharan Africa remains largely untreated.
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Affiliation(s)
- G. Richard Olds
- Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, 2500 MetroHealth Drive, Cleveland, OH 44109-1998, USA.
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30
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McGarvey ST. Schistosomiasis: Impact on childhood and adolescent growth, malnutrition, and morbidity. ACTA ACUST UNITED AC 2000. [DOI: 10.1053/spid.2000.9642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Johansen MV, Bogh HO, Nansen P, Christensen NO. Schistosoma japonicum infection in the pig as a model for human schistosomiasis japonica. Acta Trop 2000; 76:85-99. [PMID: 10936567 DOI: 10.1016/s0001-706x(00)00103-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Valuable information on human schistosomiasis japonica has been provided using primates and experimental rodent hosts. However, major drawbacks such as high costs and ethical concerns for the primate models and large biological deviations for the rodent models have led to the search for more appropriate models. Recent data on the pig indicate that this natural host for Schistosoma japonicum might be a realistic alternative. As only very few research groups have investigated the S. japonicum/pig model, the present review mainly deals with the experimental methods and the major host/parasite findings obtained from the authors own research group. With emphasis on a critical evaluation of the work, the results are compared to the scarce information existing on human schistosomiasis japonica. Like in humans, S. japonicum establishes mainly in the large intestinal veins, with high faecal egg counts during the acute phase of infection, which varies greatly within and between days. Concomitant resistance is another shared feature, but studies in pigs have indicated that the phenomenon is more complex than generally thought. Clinical signs as eosinophilia and diarrhoea with mucus and blood in the acute phase of infection and hepatomegaly, increased portal diameter, periportal fibrosis and ascites in chronic infections are common findings in both humans and pigs. Low protein diet aggravates the disease in pigs by increasing the establishment rates, the faecal egg excretion and the morbidity. A 100% cure rate is achieved when treating S. japonicum infected pigs with praziquantel at 40 mg/kg, and 4 weeks post treatment pigs remain resistant to reinfection. Lastly, human congenital S. japonicum infection has been confirmed in pigs but the implications of such infections for the pathogenesis of schistosomiasis japonica remain to be investigated.
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Affiliation(s)
- M V Johansen
- Danish Bilharziasis Laboratory, Charlottenlund, Denmark.
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32
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Abstract
Schistosomiasis is a major, worldwide cause of morbidity and mortality. Disease from the organism Schistosoma mansoni results from egg deposition in the liver, intestines, and other organs and is associated with an intense, granulomatous response from the human host. Clinical manifestations range from mild to severe intestinal forms, and hepatosplenic schistosomiasis, which is associated with hepatic fibrosis, portal hypertension, esophageal varices, and splenomegaly. This article presents information about the epidemiology, immunopathogenesis and clinical aspects of the disease, the relationship between hepatic schistosomiasis and viral infections, diagnosis, therapy, and control strategies for schistosomiasis.
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Affiliation(s)
- I Bica
- Department of Medicine, New England Medical Center, Boston, Massachusetts, USA
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33
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Li YS, Sleigh AC, Ross AG, Li Y, Williams GM, Tanner M, McManus DP. Two-year impact of praziquantel treatment for Schistosoma japonicum infection in China: re-infection, subclinical disease and fibrosis marker measurements. Trans R Soc Trop Med Hyg 2000; 94:191-7. [PMID: 10897367 DOI: 10.1016/s0035-9203(00)90274-8] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We studied a community cohort of 193 individuals exposed to endemic Schistosoma japonicum infection in the Dongting Lake region of China to assess subclinical morbidity and the 2-year benefit of curative therapy (praziquantel) administered in 1996. Prevalence and intensity of S. japonicum infection before treatment were 28% and 192 eggs per gram faeces (epg), respectively. Two years after cure, 22% of the cohort were re-infected, but with a lighter intensity (67 epg). Sixty-four subjects (37%) showed significant improvement in ultrasound parenchyma images after treatment and 51 subjects (54%) showed significant improvement of periportal fibrosis. Left-lobe enlargement also reversed (P < 0.05) and splenomegaly reversed in 6 of 8 cases and developed in only 1. Two years post-treatment a dilated portal vein became less frequent, but the decline was not significant (16% vs 11%, P < 0.05). The serum levels of laminin and collagen IV associated with re-infection and intensity and hyaluronic acid levels correlated with ultrasound findings (P < 0.01). Overall, treatment induced a marked decrease in subclinical hepatosplenic morbidity attributable to S. japonicum although low-intensity re-infection after treatment remained relatively frequent. Stratified analysis and logistic models evaluated potential confounding factors for assessment of treatment effects on hepatic fibrosis. S. japonicum infection and moderate-heavy alcohol intake interacted: improvement in parenchymal morbidity was impeded among drinkers (P < 0.05). Chemotherapy focused on at-risk residents controls prevalent subclinical hepatic fibrosis but re-infection indicates the need for complementary control strategies.
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Affiliation(s)
- Y S Li
- Australian Centre for International and Tropical Health and Nutrition, Queensland Institute of Medical Research, Herston, Brisbane, Australia.
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34
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Hernandez MG, Hafalla JC, Acosta LP, Aligui FF, Aligui GD, Ramirez BL, Dunne DW, Santiago ML. Paramyosin is a major target of the human IgA response against Schistosoma japonicum. Parasite Immunol 1999; 21:641-7. [PMID: 10583866 DOI: 10.1046/j.1365-3024.1999.00263.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Human resistance and susceptibility to schistosomiasis is associated with age and specific antibody isotype responses against worm (SWAP) and egg (SEA) antigens. In a cross-sectional study of 176 individuals infected with Schistosoma japonicum in the Philippines, strikingly similar isotype response patterns against SWAP and SEA was observed when compared to other endemic areas. Interestingly, IgA titres to SWAP correlated with older age among S. japonicum-infected individuals (n = 176, P < 0.01), suggesting a role for this isotype in protective immunity. To identify the molecular targets of human IgA, 17 high-IgA/SWAP responders were identified from the said population. IgA antibodies from the majority (14/17) of these individuals recognized a band of 97 kDa (Sj97), comigrating in immunoblots with the myofibrillar protein paramyosin. The antigen was confirmed as paramyosin by expressed sequence tag (EST)-analysis of four clones obtained by screening an adult S. japonicum cDNA library with pooled IgA antisera and mouse antiparamyosin polyclonal antibodies. The identification of paramyosin as a major target of human IgA raises its potential as a vaccine candidate that targets mucosal immune responses. Since this antigen is exposed on the parasite surface only during the lung stages, we propose that human IgA contributes to parasite attrition during schistosome migration in the lungs.
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Affiliation(s)
- M G Hernandez
- Schistosomiasis Study Group, Research Institute for Tropical Medicine, Alabang, Muntinlupa City, Philippines
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35
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Li YS, Ross AG, Sleigh AC, Li Y, Waine GJ, Williams GJ, Tanner M, McManus DP. Antibody isotype responses, infection and re-infection for Schistosoma japonicum in a marshland area of China. Acta Trop 1999; 73:79-92. [PMID: 10465049 DOI: 10.1016/s0001-706x(99)00019-4] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Antibody isotype responses to adult worm antigen (AWA) of Schistosoma japonicum and two recombinant proteins (paramyosin (PMY) and a 22 kDa tegumental membrane-associated antigen (TEG)) were analyzed in 137 individuals from an area moderately endemic for schistosomiasis in the Dongting Lake region, Hunan Province, China. The prevalence and geometric mean (GM) intensity of infection before the implementation of curative chemotherapy were 28.5% and 234.4 epg, respectively, but 9 months after treatment the prevalence (6.6%) and intensity (38.3 epg) had decreased. There was no significant difference in either the prevalence or intensity of infection between males and females. Specific IgG (total), IgG4, IgG2, IgA and IgE responses to AWA, PMY and TEG were measured by ELISA. Males produced significantly (P < 0.05) more anti-AWA total IgG, IgE, IgA, IgG4 and IgG2 antibodies, and anti-TEG IgG2 antibody than their female counterparts. The OD450 levels of anti-AWA, PMY and TEG antibody isotypes did not present clear age-dependent trends except for peak levels of anti-AWA IgG4 antibodies evident among subjects 20-29 years of age. The total IgG and IgG4 antibody profiles against AWA correlated well with current S. japonicum infections while anti-AWA IgG2, IgA and IgE antibodies did not show such an association. Anti-AWA-specific IgE antibody levels were positively correlated (r = 0.55) with anti-AWA specific IgG4 antibody levels. In addition, the overall percentage of responders (using a cut-off value obtained from normal controls) to all isotypes to AWA were higher than those observed for both the recombinant antigens. Only 18.2%, 16.8% and 7.3% of the study population were IgE responders to AWA, PMY and TEG. A longer follow-up period is required before we can more fully understand the role of IgE, if any, in protective immunity against schistosomiasis japonica.
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Affiliation(s)
- Y S Li
- Australian Centre for International and Tropical Health and Nutrition, The University of Queensland and the Queensland Institute of Medical Research, Brisbane.
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36
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Hafalla JC, Alamares JG, Acosta LP, Dunne DW, Ramirez BL, Santiago ML. Molecular identification of a 21.7 kDa schistosoma japonicum antigen as a target of the human IgE response. Mol Biochem Parasitol 1999; 98:157-61. [PMID: 10029318 DOI: 10.1016/s0166-6851(98)00160-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- J C Hafalla
- Schistosomiasis Study Group, Research Institute for Tropical Medicine, Alabang, Muntinlupa, Philippines.
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