Parasite infection and tuberculosis disease among children: a case-control study

Echinococcosis Is Associated with the Increased Prevalence of Intestinal Blastocystis Infection in Tibetans and Host Susceptibility to the Blastocystis in Mice

Blastocystis is a common human intestinal protozoan parasite. Little is known about its prevalence in echinococcosis. This study tested whether Echinococcus multilocularis infection would increase host susceptibility to Blastocystis. A total of 114 fecal samples (68 hydatid disease patients and 46 healthy people) were collected from Tibetans in the Qinghai province in China. The presence of Blastocystis was identified by sequencing of the small subunit (SSU) rRNA gene. Balb/c mice were co-infected with Blastocystis and E. multilocularis and tested for host susceptibility to Blastocystis. The overall Blastocystis prevalence was 12.3%; 16.2% in the patients and 4.4% in healthy people (p < 0.05). Sequence analysis identified three known Blastocystis genotypes, including ST1, ST2, and ST3, and one unknown genotype. Experimental dual infection significantly reduced mouse survival rate (20%), induced more severe signs, and increased intestinal damages with a higher intestinal colonization level of Blastocystis. The mouse model showed that E. multilocularis infection increases host susceptibility to Blastocystis. Our study shows a significantly higher prevalence of Blastocystis in patients with liver echinococcosis and reveals that non-intestinal E. multilocularis infection increases host susceptibility to the Blastocystis. Our results highlight that E. multilocularis infection is associated with Blastocystis. These findings remind us that more attention should be paid to the gut health of the patients with a helminth infection during clinical patient care.

Frequency, associated factors and clinical symptoms of intestinal parasites among tuberculosis and non-tuberculosis groups in Iran: a comparative cross-sectional study

BACKGROUND

Co-infection of human tuberculosis (TB) and intestinal parasites infections (IPIs) is a public health problem, especially in low- and middle-income countries. There is no data on this issue in Iran. Therefore, we investigated the prevalence of IPIs among patients with TB in Iran.

METHODS

Stool samples were collected from 161 patients with TB and 181 healthy people (non-TB group). Standard parasitological methods including direct slide smear, formalin-ether concentration, trichrome, modified Ziehl-Neelsen and chromotrope 2R staining techniques were used for detection of intestinal protozoa and helminths. Nested-PCR and sequence analysis were used to identify the genotypes of Cryptosporidium and human-infecting species of microsporidia. Data analysis was performed using SPSS version 16.

RESULTS

The frequency of IPIs in the non-TB group (16.5%) was slightly lower than in patients with TB (21.1%), although statistical significance was not observed (OR, 0.74; 95% CI, 0.43-1.27; P= 0.28). Blastocystis (11.8%) was the most common parasite detected in patients with TB. Infection with multiple parasites in the non-TB group (2.2%) was significantly lower than in patients with TB (7.5%) (OR, 0.28; 95% CI, 0.08-0.88; P=0.02). The ova of Taenia spp., Ascaris lumbricoides and Hyamenolepis nana were identified in three patients with TB (1.9%), while only one person (0.5%) in the non-TB group was infected with Enterobius vermicularis. The results of genotyping revealed two C. parvum subtype families (IIa and IId) and three E. bieneusi genotypes (Ebcar4, IH and jLD-1).

CONCLUSION

Our results showed a higher prevalence of IPIs in patients with TB in comparison with non-TB subjects. Moreover, our findings suggest a proper health education program for good personal hygiene habits, and also preventative measures to avoid the acquisition of IPIs in patients with TB.

Are intestinal helminths playing a positive role in tuberculosis risk? A systematic review and meta-analysis

BACKGROUND

Co-infection of intestinal helminthic infections (IHIs) and tuberculosis (TB) has appeared as a public health issue, especially in developing countries. Some recent studies have been carried out on the possible relevance of IHIs to TB. The current systematic review and meta-analysis was conducted to assess the prevalence and odds ratio (OR) of IHIs among TB patients and clarify the relationship between IHIs and TB disease.

METHODS

For the purpose of the study, five English databases including PubMed, Science Direct, Scopus, Web of Science (ISI), and Google scholar were searched (up to January 30, 2019) in order to find the related studies. Random-effects meta-analysis model was used to estimate the pooled prevalence, odds ratio (OR), and 95% confidence interval (CI). Inclusion and exclusion criteria were applied.

RESULTS

A total of 20 studies including 10 studies with case-control design (2217 patients and 2520 controls) and 10 studies with cross-sectional design (a total of 2415 participants) met the eligibility criteria. As shown by the random-effects model, the pooled prevalence of IHIs in TB patients was estimated to be 26% (95% CI, 17-35%; 1249/4632). The risk of IHI was higher in TB patients compared to controls but this was not statistically significant. However, according to genus/species, the pooled OR of Strongyloides stercoralis (S. stercoralis) (OR, 2.68; 95% CI, 1.59-4.54) had a significantly higher risk in TB patients compared to controls. Nevertheless, the results of random effects model showed no statistically significant association between overall pooled OR of IHIs in TB patients compared to controls in case-control studies (OR, 1; 95% CI, 0-1).

CONCLUSIONS

It is highly recommended that more precise studies should be carried out by researchers in order to better understand this association. Also, it is of great importance to include the periodic screenings for IHIs in the routine clinical care of these patients.

Blastocystis subtype 1 (allele 4); Predominant subtype among tuberculosis patients in Iran

BACKGROUND

Blastocystis and tuberculosis are two public health issues that are frequently reported in regions with low level of hygiene. Therefore, the current study aimed to investigate Blastocystis subtype and allele distribution in TB patients.

METHODS

Totally, 161 stool samples were taken from TB patients who were undergoing anti-MTB treatment. Stool samples were concentrated using conventional formalin-ether technique and examined using Lugol's iodine staining under light microscopy. DNA extraction was carried out and discriminative fragment was amplified and sequenced. With comparison in GenBank database, relevant subtypes and alleles were characterized and phylogenetically analyzed using MEGA v.7 and Tamura 3-parameter model.

RESULTS

In total, from 161 stool samples, 19 samples were suspected to be Blastocystis-positive. The expected fragment was amplified in 13 (8.07%) of samples. Accordingly, 11/13 (84.62%) of Blastocystis cases settled in urban and 2/13 (15.38%) were villagers. Close-contact with animals was also seen among 7/13 (53.84%) of samples. Subtype 1 (7/13; 53.84%) was the most prevalent followed by subtype 2 (5/13; 38.46%) and subtype 3 (1/13, 7.69%). All ST1 were allele 4, while alleles 9, 11 and 12 were seen in ST2 and allele 34 was the only allele observed in ST3. All three subtypes were clearly separated, while there was no separation between sequences from TB and non-TB patients.

CONCLUSION

Blastocystis ST1 was the most prevalent subtype in TB patients and there was no difference between Blastocystis isolates from TB and non-TB human subjects.

Tuberculosis susceptibility and protection in children

Children represent both a clinically important population susceptible to tuberculosis and a key group in whom to study intrinsic and vaccine-induced mechanisms of protection. After exposure to Mycobacterium tuberculosis, children aged under 5 years are at high risk of progressing first to tuberculosis infection, then to tuberculosis disease and possibly disseminated forms of tuberculosis, with accompanying high risks of morbidity and mortality. Children aged 5-10 years are somewhat protected, until risk increases again in adolescence. Furthermore, neonatal BCG programmes show the clearest proven benefit of vaccination against tuberculosis. Case-control comparisons from key cohorts, which recruited more than 15 000 children and adolescents in total, have identified that the ratio of monocytes to lymphocytes, activated CD4 T cell count, and a blood RNA signature could be correlates of risk for developing tuberculosis. Further studies of protected and susceptible populations are necessary to guide development of novel tuberculosis vaccines that could facilitate the achievement of WHO's goal to eliminate deaths from tuberculosis in childhood.

The Incidence of Pinworm (Enterobius Vermicularis) in Pre-school and School Aged Children in the Eastern Slovakia

Helminth infections caused by Enterobius vermicularis have a cosmopolitan character and most often affect the paediatric pre-school and school age population. The presented study was conducted to determine the prevalence of E. vermicularis in the analyzed population of children in the Eastern Slovakia. The Graham’s scotch tape method was used to investigate the presence of Enterobius vermicularis eggs in 390 specimens. The analyzed set consisted of 218 girls and 172 boys, divided by age into three groups – aged from 5 months to 2 years, aged from 3 to 6 years, and aged from 7 to 15 years. Investigation of perianal scotch tapes of children for the presence of E. vermicularis eggs revealed the prevalence of E. vermicularis was P = 3.59 %. Depending on the incidence of E. vermicularis infection, we detected no statistically significant difference (p> 0.05). The prevalence of E. vermicularis in boys was P = 4.07 %, and in girls P = 3.21 %. The highest prevalence of E. vermicularis was recorded in the group of children aged from 3 to 6 years (P = 5.03 %). Most of the samples were positive at age 4 and 5. The lowest prevalence was in the group of children aged from 5 months to 2 years (P = 0.97 %), and the prevalence of E. vermicularis in the group of children aged from 7 to 15 was P = 3.91 %. The difference in the incidence of E. vermicularis infection among different age groups of children was not statistically significant (p> 0.05).

Enterobius vermicularis nematode infection and enterobiasis currently represents a major public health problem in Slovakia. At the present its occurrence is the most frequent in the paediatric population. Therefore it is important to introduce a targeted hygienic-epidemiological measure in children’s collectives, what also should include proper and effective diagnostics and frequent recurrent therapy.

Parasitismo intestinal y tuberculosis

Introducción.La tuberculosis es coendémica en áreas con alta prevalencia de parasitismo intestinal. Se ha sugerido que, en pacientes con tuberculosis latente, la parasitosis intestinal por helmintos puede desencadenar progresión hacia la forma pulmonar activa, pero esta relación es controversial.Objetivo. Realizar una revisión narrativa de la literatura respecto a la relación existente entre el parasitismo intestinal y la infección por Mycobacterium tuberculosis.Materiales y métodos. Se llevó a cabo una búsqueda de la literatura publicada en las bases de datos ProQuest, EBSCO, ScienceDirect, Pubmed, LILACS, Embase, Trip Database, SciELO y Cochrane Library, con los términos: [Tuberculosis] AND [Intestinal diseases, parasitic] AND [Helminths]; [Tuberculosis] AND [Intestinal diseases, parasitic]; [Tuberculosis] AND [Helminths] en inglés y con sus equivalentes en español. Esta búsqueda se limitó a revisiones sistemáticas con o sin metaanálisis, estudios de cohorte y casos y controles.Resultados. Se encontraron 1 revisión sistemática, 2 estudios de cohorte y 44 estudios de casos y controles con información relevante para el desarrollo de la presente revisión.Conclusiones. La evidencia disponible fue insuficiente para afirmar que el parasitismo intestinal predispone al desarrollo de la enfermedad tuberculosa. Los estudios realizados hasta ahora han encontrado resultados estadísticamente no significativos.

Association between parasitic infections and tuberculin skin test results in refugees

BACKGROUND

Parasitic infections are known to modulate the immune response necessary for controlling Mycobacterium tuberculosis infection. We sought to investigate species-specific effects of parasite infection on M. tuberculosis infection.

METHODS

As part of the Refugee Health Assessment Program, stool examinations and tuberculin skin testing were performed on refugees seen at Boston Medical Center between 1995 and 2012. Tuberculin skin test (TST) and stool examination data were collected for 6669 refugees; 3349 (50.2%) were TST positive (≥10 mm).

RESULTS

Among TST-positive subjects, 176 (5.3%) had helminth infections and 1149 (34.3%) protozoa. After adjusting for sex, age, and country of origin, helminth and protozoan infections were not associated with TST-positivity. When species-specific effects were examined, subjects infected with Trichuris trichiura and Giardia lamblia had reduced odds of TST-positivity (adjusted OR [aOR] 0.65 [95%CI 0.44-0.96; p = 0.03] and aOR 0.79 [95%CI 0.65-0.95, p = 0.01], respectively).

CONCLUSIONS

Our findings suggest that T. trichiura and G. lamblia may provide protection against M. tuberculosis infection. This study adds to a growing body of literature suggesting that immune response modulation and susceptibility to M. tuberculosis infection is parasite species-dependent.

Prevalence and risk factors of intestinal protozoan and helminth infections among pulmonary tuberculosis patients without HIV infection in a rural county in P. R. China

Although co-infection of tuberculosis (TB) and intestinal parasites, including protozoa and helminths, in humans has been widely studied globally, very little of this phenomenon is known in China. Therefore, a cross-sectional study was conducted in a rural county of China to investigate such co-infections. Patients with pulmonary TB (PTB) undergoing anti-Mycobacterium tuberculosis (anti-MTB) treatment were surveyed by questionnaires, and their feces and blood specimens were collected for detection of intestinal protozoa and helminths, routine blood examination and HIV detection. The χ(2) test and multivariate logistic regression model were used to identify risk factors. A total of 369 patients with PTB were included and all of them were HIV negative. Overall, only 7.3% of participants were infected with intestinal protozoa, among which prevalence of Blastocystis hominis, Entamoeba spp. and Trichomonas hominis were 6.0%, 1.1% and 0.3%, respectively; 7.0% were infected with intestinal helminths, among which prevalence of hookworm, Trichuris trichiura, Ascaris lumbricoides and Clonorchis sinensis were 4.3%, 1.9%, 0.5% and 0.3%, respectively; and 0.5% were simultaneously infected with intestinal protozoa and helminths. Among patients with PTB, body mass index (BMI)≤18 (OR=3.30, 95% CI=1.44-7.54) and raised poultry or livestock (e.g., chicken, duck, pig) (OR=3.96, 95% CI=1.32-11.89) were significantly associated with harboring intestinal protozoan infection, while BMI≤18 (OR=3.32, 95% CI=1.39-7.91), anemia (OR=3.40, 95% CI=1.44-8.02) and laboring barefoot in farmlands (OR=4.54, 95% CI=1.88-10.92) were significantly associated with having intestinal helminth infection. Additionally, there was no significant relationship between duration of anti-MTB treatment and infection rates of intestinal parasites including protozoa and helminths. Therefore, preventing malnutrition, avoiding unprotected contact with reservoirs of protozoa, and improving health education for good hygiene habits, particularly wearing shoes while outdoors, are beneficial in the prevention of intestinal protozoan and helminth infection among patients with PTB.