A single-chain antibody construct with specificity of a natural IgM antibody reduces hepatic ischemia reperfusion injury in mice.

Natural immunoglobulin M (IgM) antibodies have been shown to recognize post-ischemic neoepitopes following reperfusion of tissues and to activate complement. Specifically, IgM antibodies and complement have been shown to drive hepatic ischemia reperfusion injury (IRI). Herein, we investigate the therapeutic effect of C2 scFv (single-chain antibody construct with specificity of a natural IgM antibody) on hepatic IRI in C57BL/6 mice. Compared with PBS-treated mice, C2 scFv-treated mice displayed almost no necrotic areas, significant reduction in serum ALT, AST and LDH levels, and significantly reduced in the number of TUNEL positive cells. Moreover, C2 scFv-treated mice exhibited a notable reduction in inflammatory cells after hepatic IRI than PBS-treated mice. The serum IL-6, IL-1ß, TNF-α and MPC-1 levels were also severely suppressed by C2 scFv. Interestingly, C2 scFv reconstituted hepatic inflammation and IRI in Rag1-/- mice. We found that C2 scFv promoted hepatic cell death and increased inflammatory cytokines and infiltration of inflammatory cells after hepatic IRI in Rag1-/- mice. In addition, IgM and complement 3d (C3d) were deposited in WT mice and in Rag1-/- mice reconstituted with C2 scFv, indicating that C2 scFv can affect IgM binding and complement activation and reconstitute hepatic IRI. C3d expression was significantly lower in C57BL/6 mice treated with C2 scFv compared to PBS, indicating that excessive exogenous C2 scFv inhibited complement activation. These data suggest that C2 scFv alleviates hepatic IRI by blocking complement activation, and treatment with C2 scFv may be a promising therapy for hepatic IRI.

Impact of Anti-PEG IgM Induced via the Topical Application of a Cosmetic Product Containing PEG Derivatives on the Antitumor Effects of PEGylated Liposomal Antitumor Drug Formulations in Mice.

Poly(ethylene glycol) (PEG) is used in many common products, such as cosmetics. PEG, however, is also used to covalently conjugate drug molecules, proteins, or nanocarriers, which is termed PEGylation, to serve as a shield against the natural immune system of the human body. Repeated administration of some PEGylated products, however, is known to induce anti-PEG antibodies. In addition, preexisting anti-PEG antibodies are now being detected in healthy individuals who have never received PEGylated therapeutics. Both treatment-induced and preexisting anti-PEG antibodies alter the pharmacokinetic properties, which can result in a subsequent reduction in the therapeutic efficacy of administered PEGylated therapeutics through the so-called accelerated blood clearance (ABC) phenomenon. Moreover, these anti-PEG antibodies are widely reported to be related to severe hypersensitivity reactions following the administration of PEGylated therapeutics, including COVID-19 vaccines. We recently reported that the topical application of a cosmetic product containing PEG derivatives induced anti-PEG immunoglobulin M (IgM) in a mouse model. Our finding indicates that the PEG derivatives in cosmetic products could be a major cause of the preexistence of anti-PEG antibodies in healthy individuals. In this study, therefore, the pharmacokinetics and therapeutic effects of Doxil (doxorubicin hydrochloride-loaded PEGylated liposomes) and oxaliplatin-loaded PEGylated liposomes (Liposomal l-OHP) were studied in mice. The anti-PEG IgM antibodies induced by the topical application of cosmetic products obviously accelerated the blood clearance of both PEGylated liposomal formulations. Moreover, in C26 tumor-bearing mice, the tumor growth suppressive effects of both Doxil and Liposomal l-OHP were significantly attenuated in the presence of anti-PEG IgM antibodies induced by the topical application of cosmetic products. These results confirm that the topical application of a cosmetic product containing PEG derivatives could produce preexisting anti-PEG antibodies that then affect the therapeutic efficacy of subsequent doses of PEGylated therapeutics.

Comparison of two automated commercial assays for routine detection of anti-hepatitis E Virus IgM antibodies in clinical samples.

Diagnosis of hepatitis E virus (HEV) infection relies first on detection of IgM antibodies (Ab), sometimes completed with HEV RNA detection. This study aimed to compare the performance of two automated anti-HEV IgM Ab assays. Correlation between Virclia® (Vircell) and Liaison® (Diasorin) assays was carried out on 178 routine clinical samples. Both assays were run on 67 samples from HEV RT-PCR (Altona) screened patients, and 52 Wantai® EIA (Euroimmun) tested samples. An excellent correlation was observed between both assays with an overall agreement of 96.6% (172/178), and a kappa coefficient at 0.93. In HEV RNA positive group (n=43), IgM detection rate was 93.3% (14/15) in immunocompetent patients, with both assays. In immunocompromised patients, detection rate was 75% (21/28) and 71.4% (20/28) using Virclia® and Liaison XL® assays, respectively. Virclia® and Liaison® anti-HEV IgM assays have similar performance for the detection of anti-HEV IgM Ab.

Persistence of Treponema pallidum IgM antibodies in serum: What is their meaning?

We studied the detection of Treponema pallidum (TP)-IgM antibodies in the serum of 69 patients treated for syphilis. The persistence of TP-IgM antibodies in serum for more than 3 years was the only clue to suspect an active infection and, therefore, to investigate a central nervous system involvement.

Seroprevalence of Toxoplasma gondii Antibodies and Associated Risk Factors Among Women in Zakho City, Iraq.

Toxoplasmosis, an infectious disease caused by the obligate intracellular protozoan parasite, poses varying degrees of risk, ranging from asymptomatic cases in immunocompetent individuals to severe, life-threatening conditions in immunocompromised individuals and developing fetuses, especially when infection occurs during early pregnancy. While the disease is endemic in Iraq, there is a notable lack of precise information regarding its seroprevalence among females of childbearing age and pregnant women, along with associated risk factors in the Zakho district. This cross-sectional study aimed to address this gap by determining the prevalence of anti-Toxoplasma gondii IgG and IgM antibodies using the ELISA assay. The study involved 610 females aged 18-79 years from various residential areas within Zakho district, Iraq. The findings revealed a seroprevalence of 32.46% for anti-Toxoplasma IgG antibodies and 8.86% for IgM antibodies. Significant variations in IgG antibody seroprevalence were observed across different age groups (P=0.008), with the highest prevalence noted among those aged 46-55 years (47.73%). Conversely, IgM antibody seroprevalence, while non-significant (P>0.05), displayed the highest rate of 10.05% among ages 18-25 years. The study identified residence as a variable significantly associated with toxoplasmosis. Additionally, contact with cats, marital status, a history of abortion, and the consumption of homemade food showed significant associations with anti-Toxoplasma IgM antibodies only. These findings strongly suggest that Toxoplasma gondii is a prevalent causative agent of infection in Zakho city, Iraq. This study contributes valuable insights into the seroprevalence and associated risk factors, providing a foundation for targeted interventions and further research in this region.

Insights into measles virus: Serological surveillance and molecular characterization.

BACKGROUND: Measles has been a significant public health concern in Pakistan, especially in the Khyber Pakhtunkhwa (KPK) province, where sporadic and silent epidemics continue to challenge existing control measures. This study aimed to estimate the prevalence and investigate the molecular epidemiology of the measles virus (MeV) in KPK and explore the vaccination status among the suspected individuals. METHODS: A cross-sectional study was conducted between February and October 2021. A total of 336 suspected measles cases from the study population were analyzed for IgM antibodies using Enzyme-Linked Immunosorbent Assay (ELISA). Throat swabs were randomly collected from a subset of positive cases for molecular analysis. Phylogenetic analysis of MeV isolates was performed using the neighbor-joining method. The vaccination status of individuals was also recorded. RESULTS: Among the suspected participants, 61.0% (205/336) were ELISA positive for IgM antibodies, with a higher prevalence in males (64.17%) compared to females (57.04%). The majority of cases (36.0%) were observed in infants and toddlers, consistent with previous reports. The majority of IgM-positive cases (71.7%) had not received any dose of measles vaccine, highlighting gaps in vaccine coverage and the need for improved immunization programs. Genetic analysis revealed that all MeV isolates belonged to the B3 genotype, with minor genetic variations from previously reported variants in the region. CONCLUSION: This study provides valuable insights into the genetic epidemiology of the MeV in KPK, Pakistan. The high incidence of measles infection among unvaccinated individuals highlights the urgency of raising awareness about vaccine importance and strengthening routine immunization programs.

Serum AXL is a potential molecular marker for predicting COVID-19 progression.

Background: The severity, symptoms, and outcome of COVID-19 is thought to be closely linked to how the virus enters host cells. This process involves the key roles of angiotensin-converting enzyme 2 (ACE2) and the Tyrosine protein kinase receptor UFO (AXL) receptors. However, there is limited research on the circulating levels of ACE2 and AXL and their implications in COVID-19. Methods: A control group of 71 uninfected individuals was also included in the study. According to the Guidance for Corona Virus Disease 2019 (10th edition), a cohort of 358 COVID-19 patients were categorized into non-severe and severe cases. Serum ACE2/AXL levels in COVID-19 patients were detected by enzyme-linked immunosorbent assay (ELISA) at different time points post-COVID-19 infection, including days 0-7, 8-15, 31-179 and >180 days. Serum SARS-CoV-2 IgG/IgM antibodies in COVID-19 patients at the same intervals were assessed by using an iFlash 3000 Chemiluminescence Immunoassay Analyzer. The receiver operating characteristic (ROC) curves were used to assess the diagnostic value of the biological markers, and the association between laboratory parameters and illness progression were explored. Results: Compared with the uninfected group, the levels of ACE2 and AXL in the COVID-19 group were decreased, and the SARS-COV-2 IgG level was increased. AXL (AUC = 0.774) demonstrated a stronger predictive ability for COVID-19 than ACE2. In the first week after infection, only the level of AXL was statistically different between severe group and non-severe group. After first week, the levels of ACE2 and AXL were different in two groups. Moreover, in severe COVID-19 cases, the serum ACE2, AXL, and SARS-COV-2 IgM levels reached a peak during days 8-15 before declining, whereas serum SARS-COV-2 IgG levels continued to rise, reaching a peak at day 31-180 days before decreasing. In addition, the AXL level continued to decrease and the SARS-COV-2 IgG level continued to increase in the infected group after 180 days compared to the uninfected group. Conclusions: The levels of serum ACE2 and AXL correlate with COVID-19 severity. However, AXL can also provide early warning of clinical deterioration in the first week after infection. AXL appears to be a superior potential molecular marker for predicting COVID-19 progression.

Humoral and Cellular Immune Response after Three Doses of Sinopharm [Vero Cell]-Inactivated COVID-19 Vaccine in Combination with SARS-CoV-2 Infection Leads to Hybrid Immunity.

BACKGROUND: Several vaccines against COVID-19 have been developed and licensed to enhance the immune response against SARS-CoV-2. Similarly, previous infection with SARS-CoV-2 has been shown to provide significant protection against severe infection and hospitalization. METHODS: We investigated the effect of three doses of the Sinopharm vaccine and SARS-CoV-2 infection on the specific immune response in 103 volunteers, measuring neutralizing antibodies, anti-S1 IgG, anti-RBD IgM, anti-N IgM, anti-N IgG antibodies, and INF γ. RESULTS: Our results showed that the presence of cardiovascular diseases increased the level of anti-N-IgG antibodies, while endocrinological diseases decreased the level of neutralizing antibodies and anti-N IgG antibodies, suggesting that these diseases alter the effect of vaccine-induced immunity. In addition, there was a significant decrease in anti-S1 IgG levels at 6 months and in anti-N IgG levels 18 months post-infection, while neutralizing antibodies and INF γ levels were constant at 3, 6, and 18 months post-infection. CONCLUSIONS: Our results confirm the emergence of hybrid immunity, which is the strongest and most durable compared to natural immunity or vaccine-induced immunity. Significant positive correlations were found between humoral and cellular immunity markers: neutralizing antibodies, anti-S1 IgG and anti-N IgG antibodies, and INF γ, indicating a unique coordinated response specific to COVID-19.

Evaluation of a Commercial Immuno-Chromatographic Assay Kit for Rapid Detection of IgM Antibodies against Leptospira Antigen in Human Serum

Leptospirosis is a febrile zoonotic disease. Routine diagnosis of leptospirosis is based on the detection of specific antibodies with serological tests. The aim of our study was to determine the usefulness of immunochromatographic assay (ICA), ImmuneMed Leptospira IgM Duo Rapid test kit from Korea, in rapid screening of acute leptospirosis in emergency cases with limited expertise. A total of 197 serum samples (93 positive, 104 negative) were selected randomly. The test has good diagnostic sensitivity 73% and specificity 90%. With positive predictive value of 87% and negative predictive value of 79%, this reassures patients have higher chance of correct diagnosis. This ICA is acceptable for screening of leptospirosis but confirmation with microscopic agglutination test should follow.

The research of application of nine kinds of immunoglobulin M in detection in children with respiratory tract infection / 国际检验医学杂志

Objective Analysis of the results through nine kinds of Immunoglobulin M (IgM) in children with respiratory tract infection test ,and then investigate infant′s characteristics about gender ,geographical and seasonal ,provide a reference for clinical di‐agnosis .Methods Firstly ,collection the 2 736 children′s blood in our hospital and centrifuged serum ,use indirect immunofluores‐cence (ILF) method and IgM antibody reagents to detect Legionella pneumophlia 1(LP1) ,Mycoplasma pneumoniae(MP) ,Coxiella burnetii(COX) ,Chlamydia pneumoniae(CP) ,Adenovirus(ADV) ,Respiratory syncytial virus(RSV) ,Influenza A virus(IFA) ,Influ‐enza B virus(IFB) ,Parainfluenza virus(PIV) and record the children′s information ever months ,and use the card square test to a‐nalysis .Results A total of 2 736 cases of children were detected in 918 cases (33 .5% ) with IgM antibodies ,the detection rate in descending order MP ,FluB ,PIV ,ADV ,RSV ,COX ,FluX ,CP and LP1 ,124 cases of mixed infection ,it′s 13 .51% of the total num‐ber of infections .The total number of infections in men positive 21 .02% ,12 .54% for women ,with statistical significance (P<0 . 05) ,between different sexes .The highest in age groups was the 13 years old group detection rate was 13 .49% ,followed by 35 years old group(7 .79% ) ,and there was a significant difference(P<0 .05) between the groups .The analyzed about seasonal viral infection in children ,the winter(14 .07% ) and spring(7 .79% ) higher incidence ,and prevalence of each season statistically significant (P<0 .05) .Conclusion Children in the region are mostly M P pathogen infection ,and exist differences in seasonal ,gender and age .

Detección de anticuerpos IgM contra leptospiras por un sistema comercial ELISA-IgM / Detection of IgM antibodies to leptospires by using a commercial ELISA-IgM system

Introducción: la leptospirosis humana es una zoonosis sistémica y transmisible producida por bacterias invasivas del complejo Leptospira interrogans sensu lato. Numerosos métodos se utilizan para el serodiagnóstico de esta entidad clínica, dentro de los cuales se encuentra ELISA. Objetivos: aplicar un nuevo sistema serológico comercial de ELISA, para la pesquisa de anticuerpos IgM contra leptospiras e identificar los serogrupos de leptospiras presentes en los sueros positivos por este sistema. Métodos: de pacientes sospechosos de leptospirosis se estudiaron 27 y 61 sueros con anticuerpos contra leptospiras y sin estos, respectivamente. La técnica de microaglutinación con antígenos vivos (MAT) se utilizó como método de referencia. Los sistemas comerciales de SD Leptospira ELISA-IgM, SD flujo lateral Leptospira IgM y la hemoaglutinación indirecta (HAT) fueron comparativamente empleados. Resultados: 27 sueros con anticuerpos contra leptospiras resultaron positivos por SD Leptospira ELISA-IgM, 20 por SD flujo lateral Leptospira IgM y 9 por hemoaglutinación indirecta. De 61 sueros sin anticuerpos contra leptospiras, 9 y 8 resultaron positivos, respectivamente, por SD Leptospira ELISA-IgM y por SD flujo lateral Leptospira IgM. Los serogrupos Ballum y Canicola predominaron en los sueros positivos por el sistema comercial. La coincidencia entre SD Leptospira ELISA-IgM y la técnica de microaglutinación con antígenos vivos fue de 89,77 porciento. Conclusiones: SD Leptospira ELISA-IgM muestra una mayor positividad en los sueros estudiados, lo que avalaría su posible introducción en Cuba. Se confirma la amplia reactividad del antígeno usado en SD Leptospira ELISA-IgM, lo cual sugiere mantener una activa vigilancia de laboratorio sobre los serogrupos de leptospiras, a nivel nacional

Introduction: human leptospirosis is a communicable systemic zoonosis caused by the invasive bacteria Leptospira interrogans sensu lato complex. Numerous methods are used for serodiagnosis of this disease, including the ELISA tests. Objectives: to implement a new commercial serological ELISA test (SD Leptospira ELISA-IgM, SD Bioline, Korea) for screening of IgM antibodies and for identification of Leptospira serogroups in positive sera. Methods: twenty seven and sixty one sera, with/without IgM antibodies to leptospires, respectively, were studied. They had been taken from patients suspected of having leptospirosis. The microscopic agglutination test with live antigens (MAT) was the reference method. In addition, other commercial systems such as SD Leptospira IgM Lateral Flow and indirect hemagglutination (HAT) tests were comparatively used. Results: all the 27 sera with antibodies against Leptospira were positive according to SD Leptospira ELISA-IgM, 20 sera were found positive by SD Lateral Flow Igm test and 9 sera by the indirect HAT test. Of the 61 sera without antibodies to leptospires, 9 and 8 were positive by SD Leptospira ELISA-IgM and SD Leptospira IgM Lateral Flow test, respectively. Serogroups Canicola and Ballum were predominant in positive sera tested by the commercial system under evaluation. The agreement coefficient between SD Leptospira ELISA-IgM and MAT was 89.77 percent. Conclusions: SD Leptospira ELISA-IgM showed higher positivity rate than the other systems in the studied sera; this aspect would support its possible introduction in Cuba. The great reactivity of the antigen used in the system was confirmed, which indicates that active laboratory surveillance of leptospiral serogroups should be kept nationwide

Detección de anticuerpos IgM contra leptospiras por un sistema comercial ELISA-IgM / Detection of IgM antibodies to leptospires by using a commercial ELISA-IgM system

Introducción: la leptospirosis humana es una zoonosis sistémica y transmisible producida por bacterias invasivas del complejo Leptospira interrogans sensu lato. Numerosos métodos se utilizan para el serodiagnóstico de esta entidad clínica, dentro de los cuales se encuentra ELISA. Objetivos: aplicar un nuevo sistema serológico comercial de ELISA, para la pesquisa de anticuerpos IgM contra leptospiras e identificar los serogrupos de leptospiras presentes en los sueros positivos por este sistema. Métodos: de pacientes sospechosos de leptospirosis se estudiaron 27 y 61 sueros con anticuerpos contra leptospiras y sin estos, respectivamente. La técnica de microaglutinación con antígenos vivos (MAT) se utilizó como método de referencia. Los sistemas comerciales de SD Leptospira ELISA-IgM, SD flujo lateral Leptospira IgM y la hemoaglutinación indirecta (HAT) fueron comparativamente empleados. Resultados: 27 sueros con anticuerpos contra leptospiras resultaron positivos por SD Leptospira ELISA-IgM, 20 por SD flujo lateral Leptospira IgM y 9 por hemoaglutinación indirecta. De 61 sueros sin anticuerpos contra leptospiras, 9 y 8 resultaron positivos, respectivamente, por SD Leptospira ELISA-IgM y por SD flujo lateral Leptospira IgM. Los serogrupos Ballum y Canicola predominaron en los sueros positivos por el sistema comercial. La coincidencia entre SD Leptospira ELISA-IgM y la técnica de microaglutinación con antígenos vivos fue de 89,77 porciento. Conclusiones: SD Leptospira ELISA-IgM muestra una mayor positividad en los sueros estudiados, lo que avalaría su posible introducción en Cuba. Se confirma la amplia reactividad del antígeno usado en SD Leptospira ELISA-IgM, lo cual sugiere mantener una activa vigilancia de laboratorio sobre los serogrupos de leptospiras, a nivel nacional(AU)

Introduction: human leptospirosis is a communicable systemic zoonosis caused by the invasive bacteria Leptospira interrogans sensu lato complex. Numerous methods are used for serodiagnosis of this disease, including the ELISA tests. Objectives: to implement a new commercial serological ELISA test (SD Leptospira ELISA-IgM, SD Bioline, Korea) for screening of IgM antibodies and for identification of Leptospira serogroups in positive sera. Methods: twenty seven and sixty one sera, with/without IgM antibodies to leptospires, respectively, were studied. They had been taken from patients suspected of having leptospirosis. The microscopic agglutination test with live antigens (MAT) was the reference method. In addition, other commercial systems such as SD Leptospira IgM Lateral Flow and indirect hemagglutination (HAT) tests were comparatively used. Results: all the 27 sera with antibodies against Leptospira were positive according to SD Leptospira ELISA-IgM, 20 sera were found positive by SD Lateral Flow Igm test and 9 sera by the indirect HAT test. Of the 61 sera without antibodies to leptospires, 9 and 8 were positive by SD Leptospira ELISA-IgM and SD Leptospira IgM Lateral Flow test, respectively. Serogroups Canicola and Ballum were predominant in positive sera tested by the commercial system under evaluation. The agreement coefficient between SD Leptospira ELISA-IgM and MAT was 89.77 percent. Conclusions: SD Leptospira ELISA-IgM showed higher positivity rate than the other systems in the studied sera; this aspect would support its possible introduction in Cuba. The great reactivity of the antigen used in the system was confirmed, which indicates that active laboratory surveillance of leptospiral serogroups should be kept nationwide(AU)

Detection of IgG and IgM Antibodies to Purified Keratinolytic Proteinase in Sera from Patients with Dermatophytosis by Enzyme-Linked Immunosorbent Assay

No abstract available.

Seroprevalence of rubella antibodies and effects of vaccination among healthy university women students in Korea

Since the introduction of rubella vaccination in Korea in 1982, several outbreaks of rubella have occurred. In order to examine the current seroepidemiology of rubella virus infection in Korean women of child-bearing age, the healthy university women students of Yonsei University in Seoul aged 18 approximately 26 years were chosen as a model population. A survey was carried out in the time of routine annual physical check-up. Serum specimens of 242 volunteers of healthy women university students were randomly sampled for screening rubella-specific IgG/IgM antibodies by an automated enzyme immunoassay system (Vitek System VIDAS, bioMerieux Vitek, Inc., Lyon, France). A total of 177 subjects were positive for rubella-specific IgG antibody, giving a prevalence of 73.1%. The mean +/- standard deviation of rubella-specific IgG antibody was 99.3 +/- 95.3 IU/mL. In this study, the efficiency of a vaccination was about 88%. With such a relative high proportion of susceptibility (26.9%) among university women students in child-bearing age, a extensive rubella vaccination program should be enforced to prevent possible outbreaks of congenital rubella syndrome in the future.

Establishment of ELISA method of detecting human cytomegalovirus by use of recombinant antigen pp65 and the comparative analysis with two other methods / 中华检验医学杂志

Objective To establish a new ELISA method by use of shorted recombinant antigen pp65 for detection of IgM antibodies to human cytomegalovirus (HCMV).Method According to HCMV pp65 sequence of nucleotide and amino acid, the shorted pp65 was decided by computer soft ware of protein and attained through gene engineering technique. The by computer soft ware of protein and attained through gene engineering technique. The recombinant enzyme- linked immunosorbent assay (REC-ELISA ) method was developed using pp65 recombinant protein as antigen and was applied to detecting anti-HCMV-IgM in sera. It was compared to ELISA by use of whole virus as antigen and Biocheck CMV IgM enzyme immunoassay test kit.Results To detect HCMV IgM by REC-ELISA, the best quantity of pp65 was 3.5?g percent cavity, the best dilution of HRP~*anti-HCMV IgM was 1∶[KG-*2]800 and that of serum was 1∶[KG-*2]100. The positive coefficient of variation (CV) was 9.5% in stability assay. The average CV of Inter- assay and Intra-assay was 4.5% and 9.6% respectively. The positive value of REC- ELISA was 44%, that of ELISA using whole virus was 50% and BioCheck was 45%. REC-ELISA using most suitable condition was concordant with BioCheck, which was 97.0%. Its youden′s index was 92.8% and its specificity (98.2%) was higher than that of ELISA using whole virus as antigen (90.9%), too.Conclusion REC-RLISA had good sensitivity, specificity and reproducibility. The method was easy and quick. Recombinant protein was harmless and easy gained compared with the whole virus. It can be large-scale production and standardization. Therefore, the application value and potential of REC-ELISA was very large.

Estudo de anticorpos IgM para vigilância epidemiológica da esquistossomose mansoni em área de baixa endemicidade / IgM antibodies for epidemiological vigilance of schistosomiasis mansoni in a low endemic area

O controle da esquistossomose no Estado de São Paulo iniciou-se ao final da década de 60, tendo como linhas mestras o uso de moluscidas e a de quimioterapia. Apesar da aparente redução nos níveis de infecção, o Sistema de Vigilância Epidemiológica do Estado de São Paulo tem registrado continuamente casos autóctones da doença, tendo-se observado ampliação das áreas de transmissão. Com o objetivo de buscar-se método diagnóstico mais sensível para fins epidemiológicos em áreas de baixa endemicidade, onde o exame de fezes se mostra pouco eficiente, uma técnica sorológica foi avaliada em quatro áreas consideradas endêmicas para Schistosoma mansoni (Sm) no Estado. Amostras de fezes e de sangue absorvido em papel-filtro foram coletadas de populações de quatro áreas de transmissão com diferentes perfis epidemiológicos, acompanhando-as, por um período de 2 anos, com cinco inquéritos, a intervalos semestrais. Dados de prevalência e incidência obtidos pela aplicação da reação de imunofluorescência para anticorpos IgM contra tubo digestivo de Sm (RIF-IgM) e do exame de fezes (Kato-Katz) foram analisados comparativamente nas quatro áreas estudadas com maior sensibilidade que pelo método parasitológico e detectar sazonidade em algumas das áreas, através da observação de taxas de soroconversão de RIF-IgM. Esta soroconversäo, passando de negativo para positivo, indicando provável infecção recente, foi mais frequente nos inquéritos realizados no primeiro semestre do ano (pós-veräo). A RIF-IgM demonstrou sert útil para estudos epidemiológicos da esquistossomose, podendo constituir método diagnóstico, tanto na fase aguda como crônica. (AU)

The control of schistosomiasis in the State of S"o Paulo started at the end of the sixties. Themain control measures included the application of molluscicides and chemotherapy. Despite the apparentdecrease of the infection levels, the Epidemiological Vigilance System of the State has continually recordedcases of the disease, and expansion of transmission areas has been observed. Since the stool examinationshowed to be insufficiently sensitive for epidemiological purposes in areas with low transmission, aserological technique was evaluated in four schistosomiasis endemic areas of the State with the aim offinding a more efficient diagnostic method. For a period of two years, five follow-up measures of prevalenceand incidence rates were obtained for the four areas, through the stool examination (Kato-Katz method)and detection of IgM antibodies to gut antigens by the immunofluorescence test (IgM-IFT) on filter paperblood samples. The comparative analysis of the data showed the occurrence of seasonal transmission insome of the studied areas, detected by the observation of differences in the seroconversion taxes.Seroconversion from IgM-IFT negative to positive, indicating newly acquired Schistosoma mansoniinfection, was observed more frequently in surveys carried out after summer holidays.The IgM-IFTproved to be a useful technique for epidemiological purposes in shistosomiasis, so that it can be appliedfor diagnosis of both acute and chronic forms of the disease. . (AU)