The Relationship of Latent Toxoplasmosis and Cigarette Smoking: Seroprevalence, Risk Factor, and Case-Control Study in Fars Province, Southern Iran.

Toxoplasmosis is a parasitic disease with worldwide prevalence. Despite the relatively similar effects of toxoplasmosis and smoking on alteration in neurotransmitters, especially dopamine, little is known about the relation of Toxoplasma gondii infection and addiction to cigarette smoking. Therefore, the main objective of this study was to assess the relationship between latent toxoplasmosis and smoking. Through a case-control study, 216 regular cigarette smokers and 324 nonsmoker age- and gender-matched subjects were evaluated for anti-T.gondii IgG antibodies with enzyme-linked immunosorbent assay (ELISA). During the sampling, a structured questionnaire was used to obtain the demographic information of participants and the risk factors of acquired Toxoplasma. The median ages of case and control groups were 51.04 ± 18.1 (22-97 years) and 51.03 ± 16.5 (21-89 years), respectively (p = 0.99). Anti-T.gondii IgG antibodies were detected in 44 (20.37%) cases and in 135 (41.67%) controls. There was a statistically significant difference for the positivity rate between the smokers and the control group (OR = 0.35; 95%CI: 0.19-0.65; and p = 0.001). The overall prevalence was 33.14%. This study indicated the inverse association between seropositivity to Toxoplasma infection and cigarette smoking. This relationship could be due to the changes that latent toxoplasmosis has on the neurotransmitters, especially dopamine, which needs more research.

Prevalence and Predictors of Toxoplasma gondii Infection in Psychiatric Inpatients in Fars Province, Southern Iran.

Background: Psychiatric patients are at increased risk of exposure to Toxoplasma gondii infection, which may be linked to their living facilities and behaviors. Limited knowledge on the prevalence of T. gondii infection and its associated risk factors in psychiatric patients are available to the international medical communities. Thus, the aim of the current study was to assess seroprevalence of T. gondii and its associated risk factors in psychiatric inpatients in Fars Province, southern Iran. Methods: This cross-sectional study was carried out on psychiatric patients hospitalized in Ibn Sina Hospital affiliated to Shiraz University of Medical Sciences, Fars Province, southern Iran, March to July 2021. Blood samples were collected from 318 psychiatric patients and assessed for the detection of IgG against T. gondii using enzyme-linked immunosorbent assay (ELISA). Moreover, structured questionnaires were completed for the participants at the time of sampling. Logistic regression analysis was used to assess possible associations between the latent toxoplasmosis and the variables. Results: The overall seroprevalence of anti-T. gondii IgG in psychiatric inpatients was 22.3% (71/318; 95% CI = 17.9-27.3). Multivariate analyses revealed that age > 30 years [adjusted odds ratio (AOR) = 2.24, 95% CI = 1.10-4.60, p = 0.03], contact with cats (AOR = 2.52, 95% CI = 1.14-5.58, p = 0.03), raw vegetable consumption (AOR = 3.65, 95% CI = 1.74-7.65, p = 0.001), raw/undercooked meat consumption (AOR = 4.30, 95% CI = 1.47-12.63, p = 0.008), suicide attempt (AOR = 3.77, 95% CI = 1.58-8.97, p = 0.003) and cigarette smoking history (AOR = 0.38, 95% CI = 0.17-0.83, p = 0.02) were independent risk factors for T. gondii infection. Conclusion: The current results demonstrated that contact with cats, raw vegetable consumption and raw/undercooked meat consumption were independent risk factors for T. gondii seropositivity. Moreover, the current study showed significant associations between seropositivity of T. gondii and suicide attempts as well as negative associations between seropositivity of T. gondii and cigarette smoking in psychiatric inpatients using multivariate logistic regression.

Indirect immunofluorescence assay using embryonated eggs of Toxocara in human toxocariasis diagnosis is unreliable due to autofluorescence nature.

Toxocariasis is caused by infection with the nematode species Toxocara canis and Toxocara cati. Serological methods using eggs, larvae and adult worms of Toxocara spp. as antigen have been used for the diagnosis of human toxocariasis. The current study aimed to evaluate indirect immunofluorescence assay (IFA) using embryonated eggs of Toxocara for diagnosis of human toxocariasis. A total of 58 sera including twenty sera from patients with toxocariasis, 20 from healthy persons and 18 from patients with other parasitic infections were collected and used for the study. The embryonated eggs of Toxocara were prepared as antigen. Indirect immunofluorescence assay was performed using the frozen section of uterus containing embryonated T. canis eggs and unembryonated T. cati eggs. All serum samples had a positive reaction using IFA. The eggs of Toxocara as antigen exposed to the serum samples of toxocariasis, other parasitic infections and healthy persons, followed by IFA gave a bright greenish-yellow fluorescence. A number of samples such as eggs of Toxocara, Toxascaris, Trichuris and strongyloides larvae, and adult worm of Ancylostoma exhibited the bright greenish-yellow autofluorescence under fluorescent microscope. IFA using cryocut of embryonated eggs of Toxocara cannot be used for the diagnosis of human toxocariasis due to the existence of autofluorescence of the unembryonated and embryonated eggs, the second stage larva and adult worms of Toxocara spp.

Dermal microfilariae of dogs, jackals and cats in different regions of Iran.

BACKGROUND: Due to the complexity of retrieving skin-dwelling microfilariae, filarioids of dogs presenting dermal microfilariae (e.g. Cercopithifilaria spp., Onchocerca lupi) are relatively unknown compared to Dirofilaria spp. and Acanthocheilonema spp. whose microfilariae circulate in the blood. Although Cercopithifilaria spp. and O. lupi filarioids are distributed worldwide, there is a paucity of information on their occurrence in Iran. The aim of this study was to investigate these filarioids in a large population of dogs from different regions of Iran. METHODS: From October 2018 to September 2020, skin biopsies were obtained from dogs housed in shelters (n = 557) and privately owned dogs (n = 26) in seven provinces of Iran (Hamedan, Kermanshah, Yazd, Mazandaran, Khuzestan, Lorestan, Esfahan), as well as from three road-killed jackals (Canis aureus) and three cats (Felis catus) in Hamedan province. The skin biopsies were first soaked in saline solution at room temperature overnight, and examined for dermal microfilariae under the microscope. Positive skin specimens and sediments were tested by PCR for a 304-bp region of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene and amplicons were sequenced. RESULTS: Microfilariae of Cercopithifilaria spp. were found in skin biopsies of 32 of the 583 (5.5%) dogs tested, with infection rates of up to 25% in Kermanshah. No microfilariae were recovered from skin biopsy samples collected from dogs in Khorramabad and Ahvaz, nor from the examined jackals and cats. None of the privately owned dogs were found to be infected. Morphologic and morphometric characteristics of the microfilariae were consistent with C. bainae. Eighteen skin samples were positive for the cox1 gene, of which 15 sequences showed a nucleotide identity of 100% and three of 93.4% with the reference sequence of C. bainae available in GenBank (haplotype I; GenBank accession number: JF461457). CONCLUSIONS: The data from this study broadens current knowledge on the geographical distribution of C. bainae in dogs in Middle Eastern countries. Further studies on different wild canine species in the country (e.g. jackal, fox, wolf) could provide further information on the epidemiology of these filarioids. A particular focus should be put on zoonotic O. lupi given the reports of its presence in human patients from this country.

Introduction of protocols for mass production of Toxoplasma gondii tachyzoites of the genotype II PRU strain.

Background: Few investigations of genotype II of Toxoplasma gondii, the most prevalent form of the Toxoplasma parasite in humans, have been carried out on due to the rapid conversion of tachyzoites to bradyzoites in its life cycle. The current study aimed to create animal and in vitro models for production of the tachyzoites of the Prugniaud (PRU) genotype II strain. Methods: To develop an immunocompromised model and obtain tachyzoites of the PRU strain, BALB/c mice were orally treated with dexamethasone (10 mg/kg), cyclophosphamide (36 mg/kg), and cyclosporine (18 mg/kg) from 5 days prior to inoculation. Then, 10-15 tissue cysts of PRU strain were inoculated intraperitoneally into the mice. The tachyzoites obtained from mice were then cultivated in a HeLa cell culture. The resulting yield of tachyzoites was cryopreserved in 92% fetal calf serum, 8% dimethyl sulfoxide. The infectivity of these tachyzoites was evaluated using in vivo and in vitro examinations. Results: Numerous tachyzoites were observed in the peritoneal fluid of the immunosuppressed mice within 10-15 days after inoculation, and many tachyzoites were harvested from the HeLa cell culture. Trypan Blue staining showed 80% viability of the tachyzoites recovered from cryopreservation and this was confirmed by HeLa cell culture. In addition, mice infected intraperitoneally with the recovered tachyzoites presented with cysts in the brain after 2 months. Conclusion: We have developed an animal model for mass production of T. gondii tachyzoites of the PRU strain. This method can provide fresh viable tachyzoites of Toxoplasma gondii for use as and when required in future investigations.

Global prevalence and associated risk factors of diarrheagenic Giardia duodenalis in HIV/AIDS patients: A systematic review and meta-analysis.

Giardia duodenalis is one of the leading causes of diarrhea, mostly in underdeveloped nations of Africa and Asia. The present review provides insights into the prevalence, odds ratios (ORs) and associated risk factors of giardiasis in HIV/AIDS patients. Four major English databases (Web of Science, PubMed, Scopus, and Google Scholar) were excavated for relevant literature without time limitation until 20 November 2020. Next, meta-analysis was performed using a random-effects model and 95% confidence intervals (CIs). As well, heterogeneity among studies was evaluated using Cochran's Q and the I2-statistic. Totally, 19,218 HIV/AIDS patients in 130 studies were examined, showing a 5% (95% CI: 4.2%-6%) pooled prevalence. Also, the weighted random-effects OR of G. duodenalis infection among HIV/AIDS patients in comparison with their controls in 48 case-control studies was estimated as 1.71% (95% CI: 1.1%-2.66%, p = 0.016). Based on sensitivity analysis, there was no remarkable variation in the pooled OR upon omitting individual studies. Diarrhea was a potent risk factor, since HIV/AIDS patients with diarrhea were 3.8-times (95% CI: 1.6-8.9, p = 0.002) more prone to G. duodenalis infection than those without diarrhea. Moreover, the prevalence of the parasitic infection was 1.2-times higher in patients without antiretroviral therapy (ART) than those with ART (p = 0.312). Meta-regression was employed to evaluate the possible association between G. duodenalis frequency in HIV/AIDS patients and some variables such as sample size, publication year, and HDI. Additionally, the pooled prevalence of G. duodenalis infection was estimated based on several subgroups, including publication years, WHO regions, countries, continents, country incomes, and CD4+ T-cell levels. Altogether, the epidemiology of giardiasis in HIV/AIDS patients and its association with various risk factors is still open to question and requires more detailed and comprehensive investigations.

Seroprevalence of Toxocara Infection among Asthmatic Children in Shiraz City, Southern Iran.

BACKGROUND: Human toxocariasis is caused by Toxocara canis and T. cati, the nematodes in the intestine of dogs and cats, respectively. Since the association between asthma and toxocariasis is controversial, the aim of the present study was to investigate the seroprevalence of Toxocara infection among asthmatic children in comparison with healthy children. METHODS: This case-control study was conducted on 92 asthmatic and 91 healthy children aged 1-16 years old in Shiraz City, Southern Iran in 2019-2020. The serum samples were tested for IgG anti-Toxocara antibodies by ELISA method using the T. canis larval excretory-secretory (E/S) antigens. The collected data were analyzed using SPSS software. RESULTS: The seroprevalence of toxocariasis in asthmatic patients was higher than the healthy children with no significant difference in Toxocara seropositivity between two groups (9.8% vs 8.8%, P = 0.817). The association between Toxocara infection and variables such as gender and age were not statistically significant. CONCLUSION: There was no significant association between toxocariasis and childhood asthma. Further study on different regions such as urban and rural areas with a large sample size and using questionnaire for considering risk factors of asthma and toxocariasis is recommended.