Ineffectiveness of TF-Test® and Coproplus® Methods in Strongyloides stercoralis Infection Diagnosis.

PURPOSE: S. stercoralis diagnosis is currently performed by parasitological methods, mainly by Baermann-Moraes (BM), although Agar Plate Culture (APC) presents a higher sensitivity. New techniques, such as TF-Test® and Coproplus® have been suggested as more practical alternatives. The aim of this study was to evaluate the sensitivity of TF-Test® and Coproplus®, compared with APC, BM and Spontaneous Sedimentation (SS) methods. METHODS: One-hundred and forty male alcoholic patients, who provided three stools samples collected on alternate days, were included in this study. The most frequently found parasite was S. stercoralis, 20% (28/140), and the most sensitive method was APC, 96.4% (27/28), followed by BM, 89.3% (25/28) and SS, 57.1% (16/28). TF-Test® and Coproplus® presented a sensitivity of 46.4 (13/28) and 39.3% (11/28), respectively. In samples with a parasitic load of 1-10 larvae/g of feces, which occurred in 39.3% (11/28) of the infected patients, both the TF-Test® and Coproplus® methods demonstrated sensitivities of 18.2% (2/11), while APC and BM methods reached a sensitivity of 100% (11/11) (p < 0.05). For other intestinal helminth infections, TF-Test® and Coproplus® sensitivities were 22.2 (4/18) and 11.1% (2/18), respectively, this being lower than the SS, 66.7% (12/18) (p < 0.05). On the other hand, for protozoa infection diagnosis, TF-Test® and Coproplus® presented the highest sensitivities, 62.2 (46/74) and 43.2% (32/74), respectively. CONCLUSION: TF-Test® and Coproplus® methods presented the lowest sensitivities for S. stercoralis and other helminth infection diagnosis; therefore, they can be indicated for use in parasitological diagnosis, only when associated with other more effective methods of helminth identification.

Alcohol consumption alters anti-Strongyloides stercoralis antibodies production.

Individuals infected with Strongyloides stercoralis have been reported to produce different immunoglobulins isotypes, yet few studies have evaluated their use in strongyloidiasis diagnosis. The aim of this work was to evaluate the immunoreactivity of different classes and subclasses of anti-S. stercoralis circulating antibodies in alcoholic patients by ELISA and to perform immunoblotting in samples with discordant results between parasitological and immunological methods. 345 male patients with a clinical diagnosis of alcoholism hospitalized at a reference center for alcoholics in Salvador, Bahia, Brazil, were included in this study. The fecal samples were examined by three different parasitological methods (spontaneous sedimentation, Baermann-Moraes and Agar Plate Culture methods). The ELISA was performed for the detection of IgG, IgG1, IgG4, IgE and IgA1 anti-S. stercoralis. Immunoblotting, for the detection of specific IgA1, was used to elucidate discordant results between parasitological and immunological methods. S. stercoralis infection frequency in alcoholic patients by parasitological methods was 21.4% (74/345). Although IgE-ELISA demonstrated a high sensitivity and specificity in non-alcoholic patients, about 30% (22/74) of alcoholics with larvae in feces were negative. IgG1-ELISA detected the lowest frequency of antibodies in alcoholic patients with larvae in feces, only 57% (42/74). IgG4-ELISA was the best assay for S. stercoralis infection immunodiagnosis. Immunoreactivity in the immunoblotting for IgA1 at 90, 75, 26 and/or 17 kDa bands was observed in 92% (33/36) of alcoholics with larvae excretion and negative ELISA for one or more antibody isotypes. In conclusion, IgG4-ELISA showed the highest sensitivity and specificity, thus demonstrating its superiority for strongyloidiasis immunodiagnosis in alcoholic and non-alcoholic individuals. Both, IgE and IgG1-ELISA presented high sensitivities and specificities for S. stercoralis infection diagnosis in non-alcoholics, however there was low reactivity in alcoholic individuals. This can be associated with an increased susceptibility to severe strongyloidiasis in these patients. IgA1-immunoblotting can be used to confirm S. stercoralis infection when there are discordant results between parasitological methods and ELISA.

Enteroparasitoses e aspectos socioeconômicos em pacientes alcoolistas / Intestinal parasites and socioeconomic aspects of alcoholic patients

Introdução: as enteroparasitoses constituem um problema de saúde pública que atinge as populações mais vulneráveis. O alcoolismo é um problema que afeta milhões de pessoas em todo o mundo, apresenta efeitos nocivos à saúde dos indivíduos e predispõe à infecção por S. stercoralis e às formas mais graves da estrongiloidíase. Objetivo: avaliar a prevalência da infecção das enteroparasitoses, bem como fatores socioeconômicos e sanitários de pacientes alcoolistas atendidos em um centro de tratamento especializado em Salvador, Bahia. Metodologia: trata-se de um estudo transversal, realizado com pacientes alcoolistas (n=277), do sexo masculino, atendidos em um centro de tratamento entre julho de 2014 e junho de 2017. O estudo foi realizado através da aplicação de um questionário estruturado para obtenção de dados socioeconômicos, demográficos e sanitários, sendo solicitadas, ainda, pelo menos duas amostras de fezes em dias alternados. O diagnóstico parasitológico foi realizado pelos métodos de sedimentação espontânea, Baermann-Moraes e cultura em placa de ágar. Resultados: a média de idade dos pacientes inclusos foi de 44,8 ± 9,5 anos. Verificouse que 35,7% dos pacientes estavam infectados com algum enteroparasito e, desses, 30,3% eram monoparasitados. Os parasitos mais frequentes foram S. stercoralis, Endolimax nana e ancilostomídeos, correspondendo 16,6%, 11,2% e 5,8%, respectivamente. Conclusão: dessa forma, S. stercoralis foi o parasito mais frequente, e a associação entre a infecção por esse parasito e o alcoolismo pode levar à estrongiloidíase grave. A elevada frequência de enteroparasitoses nesses pacientes, principalmente por protozoários, deve-se à ausência de higiene pessoal, pois esses indivíduos são suscetíveis à infecção oral fecal. A implementação de medidas de saneamento básico e de campanhas de conscientização para prevenção de infecções parasitárias é imprescindível para a saúde das populações mais vulneráveis.

Introduction: intestinal parasitoses are a public health issue that notably affects vulnerable populations. Alcoholism is a problem that affects millions worldwide by causing damaging effects to the health of individuals as it predisposes them to that infection through stercralisàs and more evolved forms of strongyloidiasis. Objective: evaluate the prevalence of intestinal parasite infections as well as socioeconomic and sanitation factors in a population of alcoholic patients at a specialized treatment facility in Salvador, Bahia. Methodology: this cross-sectional study was carried out with male alcoholic patients (n=277) at a treatment facility from July/2014 to June/2017. The research data were collected through a structured questionnaire aimed to obtain socioeconomic, demographic and sanitation information. Stool tests were ordered in alternate days. The parasitological diagnosis was based on methods of spontaneous sedimentation, Baermann-Moraes and Agar plate growth medium. Results: the patients' average age was 44,8 ± 9,5 years. A total of 35% of the patients was infected with a type of enteroparasite, of whom 30,3% was mono-infected. The most commonly found parasites were S. stercoralis, Endolimax nana and hookworm, corresponding to 16,6%, 11,2% e 5,8%, respectively. Conclusion: as such, S. Stercoralis was the most frequent parasite in this population and the association between the infection by this parasite and alcoholism may lead to severe strongyloidiasis. The high rates of enteroparasitism in those patients, particularly protozoa, are due to the lack of adequate personal hygiene, given those individuals are prone to acquire infections transmitted through the oral fecal route. An implementation of public health sanitation measures and the launch of public awareness campaigns in order to prevent parasite infections are vital to the health of vulnerable populations.