Seroprevalence of Toxoplasma gondii infection in cancer patients: A systematic review and meta-analysis

Prevalence of Human Toxoplasmosis in Spain Throughout the Three Last Decades (1993-2023): A Systematic Review and Meta-analysis

Humans are infected by Toxoplasma gondii worldwide and its consequences may seriously affect an immune deprived population such as HIV and transplanted patients or pregnant women and foetuses. A deep knowledge of toxoplasmosis seroprevalence in Spain is needed in order to better shape health policies and educational programs. We present the results of the first systematic review and meta-analysis on the human prevalence for this disease in Spain. Databases (PubMed, Web of Science, SCOPUS and Teseo) were searched for relevant studies that were published between January 1993 and December 2023 and all population-based cross-sectional and longitudinal studies reporting the human seroprevalence in Spain were revised. Within the population analysed, our targeted groups were immunocompetent population, pregnant women and immunocompromised patients. Among 572 studies and 35 doctoral theses retrieved, 15 studies and three doctoral theses were included in the meta-analysis. A random effects model was used for the meta-analyses due to the high heterogeneity found between studies (I2: 99.97), since it is a statistically conservative model, in addition to allowing better external validity. The global pooled seroprevalence was 32.3% (95% CI 28.7-36.2%). Most of the studies carried out were in pregnant women and the meta-analysis reported that the pooled seroprevalence of toxoplasmosis in pregnant women in Spain was 24.4% (24,737/85,703, 95% CI 21.2-28.0%), based on the random effects model. It is recommended to continue monitoring the seroprevalence status of T. gondii in order to obtain essential guidelines for the prevention and control of the infection in the population.

The opposing effect of acute and chronic Toxoplasma gondii infection on tumor development

BACKGROUND

The interplay between Toxoplasma gondii infection and tumor development is intriguing and not yet fully understood. Some studies showed that T. gondii reversed tumor immune suppression, while some reported the opposite, stating that T. gondii infection promoted tumor growth.

METHODS

We created three mouse models to investigate the interplay between T. gondii and tumor. Model I aimed to study the effect of tumor growth on T. gondii infection by measuring cyst number and size. Models II and III were used to investigate the effect of different stages of T. gondii infection on tumor development via flow cytometry and bioluminescent imaging. Mouse strains (Kunming, BALB/c, and C57BL/6J) with varying susceptibilities to tumors were used in the study.

RESULTS

The size and number of brain cysts in the tumor-infected group were significantly higher, indicating that tumor presence promotes T. gondii growth in the brain. Acute T. gondii infection, before or after tumor cell introduction, decreased tumor growth manifested by reduced bioluminescent signal and tumor size and weight. In the tumor microenvironment, CD4+ and CD8+ T cell number, including their subpopulations (cytotoxic CD8+ T cells and Th1 cells) had a time-dependent increase in the group with acute T. gondii infection compared with the group without infection. However, in the peripheral blood, the increase of T cells, including cytotoxic CD8+ T cells and Th1 cells, persisted 25 days after Lewis lung carcinoma (LLC) cell injection in the group with acute T. gondii. Chronic T. gondii infection enhanced tumor growth as reflected by increase in tumor size and weight. The LLC group with chronic T. gondii infection exhibited decreased percentages of cytotoxic CD8+ T cells and Th1 cells 25 days post-LLC injection as compared with the LLC group without T. gondii infection. At week 4 post-LLC injection, chronic T. gondii infection increased tumor formation rate [odds ratio (OR) 1.71] in both KM and BALB/c mice.

CONCLUSIONS

Our research elucidates the dynamics between T. gondii infection and tumorigenesis. Tumor-induced immune suppression promoted T. gondii replication in the brain. Acute and chronic T. gondii infection had opposing effects on tumor development.

Dimedone nanoparticle as a promising approach against toxoplasmosis: In vitro and in vivo evaluation

Toxoplasma gondii, an intracellular parasite, has shown drug resistance and therapeutic failure in recent years. Dimedone (DIM) has been introduced as a new chemical compound with anti-bacterial and anti-cancer properties. The aim of this study was to investigate the potential protective role of DIM nanoparticles in an animal model of toxoplasmosis. Cytotoxicity of DIM on Vero cell line assessed using MTT, and the effect of DIM on Toxoplasma gondii was evaluated by counting the number of parasites compared to the control group in vitro. The rate of pathogenesis and virulence of the parasite was checked on the liver cells of the animal model using hematoxylin-eosin staining. Furthermore, various parameters indicating oxidative stress were compared in mouse liver tissue in different groups. The release of the nanoparticle form was significantly longer than the free drugs. The IC50 of Nano-DIM was 60 µM and the reduction of intracellular parasite proliferation in the group Nano-DIM and Nano-PYR (Nano-primethamine) was significantly lower than the free drugs in vitro. Histopathology examination in the groups treated with dimedone nanomedicine showed that the degree of disintegration of the epithelium of the central vein of the liver and infiltration and vacuolization of liver cells were lower compared to the toxoplasmosis group. Additionally, the level of some oxidative stress indicators was observed to be lower in the nano-treated groups compared to other groups. The results of this study showed DIM can be used as a promising compound for anti-T. gondii activity and can prevent the proliferation of it in cells.

Latent Toxoplasmosis among Breast Cancer Patients in Jahrom, South of Iran

Objective

Reactivation of latent toxoplasmosis is the main cause of severe infection among immunocompromised patients, including patients with cancer. Hence, this study is aimed at screening the status of Toxoplasma gondii infection among breast cancer patients by serological and molecular methods and determining their associated risk factors in Jahrom County, Fars Province, south of Iran.

Methods

One hundred and seven women with breast cancer (aged 34 to 80 years) were screened for anti-T. gondii antibodies (IgG and IgM) during 2019-2020. A questionnaire regarding demographic factors was filled out by participants. Molecular detection was performed by polymerase chain reaction (PCR) using the primer pair targeting the repetitive element (RE) gene of T. gondii. The risk factors and demographic data were analyzed by SPSS software (ver. 20, Chicago, IL, USA) using the Chi-squared test.

Results

Anti-T. gondii IgG was detected in 45.8% (49/107) of the patients, which indicates latent infection, but anti-T. gondii IgM and PCR were negative in all samples. Demographic factors revealed a statistically significant increased T. gondii seropositivity among nonmenopause cancer patients (P < 0.0005), patients without previous breast cancer (P = 0.0001), and human epidermal growth factor receptor 2- (HER2-) negative patients (P = 0.00002). As such, patients with a history of previous abortions and who were at stages II, III, and IIII of cancer had higher seropositivity rates than patients without a history of previous abortions or who were at stage I cancer, but the statistical analysis was not significant. We did not find a statistically significant association between T. gondii seropositivity and other risk factors of toxoplasmosis (e.g., education level, type of water source, washing raw fruits and vegetables, consumption of raw or undercooked meat, and contact with soil, cats, and domestic animal).

Conclusion

A high seroprevalence rate of latent T. gondii infection was detected among patients with breast cancer; hence, these patients may be at high risk for reactivation of latent infection. Screening of T. gondii infection is recommended to detect active infection among patients with malignancies.

Toxoplasma infection and Rhesus blood group system: A systematic review and meta-analysis

BACKGROUND

Toxoplasmosis is one of the most common infections in humans and animals, which is caused by an obligate intracellular opportunistic parasite known as Toxoplasma gondii (T. gondii). Some data have shown that both Rhesus (Rh)-positive and Rh-negative individuals differ in response to biological factors, including Toxoplasma infection. Therefore, this systematic review and meta-analysis was conducted to investigate the scientific evidence regarding the possible association between the Rh blood group and Toxoplasma infection and to determine the seroprevalence of T. gondii in the Rh blood group system.

METHODS

The research was conducted on PubMed, ScienceDirect, ProQuest, and Google Scholar databases until January 2023. Twenty-one cross-sectional studies were included with a total of 10910 people. The data were synthesized using a random effect model with 95% confidence intervals (CIs).

RESULTS

The overall prevalence of T. gondii was calculated at 32.34% (CI 95%: 28.23-36.45%) and 33.35% (CI 95%: 19.73-46.96%) in Rh-positive and Rh-negative blood groups. In addition, the pooled OR for the relationship between the Rh blood group and the seroprevalence of T. gondii was 0.96 (95% CI: 0.72-1.28).

CONCLUSIONS

This meta-analysis showed a high prevalence of Toxoplasma infection in both Rh-negative and positive blood groups. This systematic review and meta-analysis revealed that no significant association was found between toxoplasmosis and Rh factor. Because of the limited number of studies in this field, more research is recommended to determine the exact relationship between toxoplasmosis and the Rh factor.

Effect of maternally derived antibodies on two commercial vaccines in changes of serum antibody titres against distemper in puppies

BACKGROUND

Maternally derived antibodies (MDA) have protection against canine distemper virus (CDV) in the first weeks of puppies' life. However, MDA decreases with age. The most important and effective factor on immunization is timely vaccination. But in recent years, there were some outbreaks of CDV among puppies in Iran and this problem could be related to vaccine failure.

OBJECTIVES

The aim of this study is to evaluate the possible effect of MDA titre on vaccines against CDV and the efficacy of two commercial vaccines by using the enzyme-linked immunosorbent assay (ELISA).

METHODS

In this regard, 24 healthy 8-week old terrier puppies were selected and divided into three identical groups based on a randomized, double-blind comparative trial. The control group was injected normal saline, and group A was vaccinated by the vaccine namely Biocan L (Bioveta, Czech Republic), and the group B was vaccinated by the other vaccine called Duramune Max 5 + LCI/GP (Fort Dodge Animal Health, USA). The vaccines were used for the puppies between 8 and 16 weeks of age and in every 4 weeks.

RESULTS

The results showed that the response of both vaccines was satisfactory, and no significant difference was observed between them. Moreover, the MDA in the control group reached an unprotective level in all puppies prior to their 14 weeks of age. In the vaccinated groups, after the second vaccine, all puppies in both groups reached protective levels.

DISCUSSION

This is the first study on evaluation of two commercial vaccines in changes of serum antibody titres against distemper in puppies in Iran.

CONCLUSION

It is recommended that veterinarians during consulting use the ELISA to measure antibody titres to optimize the vaccination schedule and reduce the cost of vaccination failure. This is of paramount importance for puppies.

Beneficial Effect of Toxoplasma gondii Infection on the Prognosis of Breast Cancer Was Modified by Cytokines

Background

Animal experiments have shown the anticancer activity of Toxoplasma gondii (T. gondii), but its effect on the prognosis of cancer patients is unclear. Thus, the present study aimed to investigate the prognostic role of anti-T. gondii IgG in breast cancer patients and the modification effect of cytokines.

Methods

A total of 1121 breast cancer patients were recruited between 2008 and 2018 and followed up until December 31, 2021. Anti-T. gondii IgG and cytokines were measured using an enzyme-linked immunosorbent assay (ELISA) kit and a multiplex assay platform. Endpoints were overall survival (OS) and progression-free survival (PFS). Survival and multiplicative interaction analyses were performed using multivariate Cox regression models.

Results

According to the cutoff value of optical density (OD=0.111), 900 (80.29%) and 221 (19.71%) patients were divided into two groups: low or high anti-T. gondii IgG. Compared to patients with a low anti-T. gondii IgG level, the adjusted hazard ratios (HRs) of OS and PFS for patients with high anti-T. gondii IgG levels were 0.60 (95% confidence interval (CI): 0.37-0.99) and 0.67 (0.46-0.98), respectively. These associations were profound among patients with a high cytokine score (HR=0.29, 95% CI: 0.10-0.82 for OS; HR=0.30, 95% CI: 0.13-0.69 for PFS), accompanied by a significant interaction between the level of anti-T. gondii IgG and the cytokine score (P _interaction=0.019 for PFS); interleukin-17 (IL-17) and interleukin-9 (IL-9) were the main contributors to the interaction.

Conclusion

Anti-T. gondii IgG was found to be beneficial to breast cancer survival, especially in women with systematic inflammation and high IL-17 or IL-9 levels, suggesting the potential of T. gondii as a prognostic marker and a novel immunotherapy approach for cancer patients.

Toxoplasma gondii Infection in Marine Animal Species, as a Potential Source of Food Contamination: A Systematic Review and Meta-Analysis

PURPOSE

Many marine animals are infected and susceptible to toxoplasmosis, which is considered as a potential transmission source of Toxoplasma gondii to other hosts, especially humans. The current systematic review and meta-analysis aimed to determine the prevalence of T. gondii infection among sea animal species worldwide and highlight the existing gaps.

METHODS

Data collection was systematically done through searching databases, including PubMed, Science Direct, Google Scholar, Scopus, and Web of Science from 1997 to July 2020.

RESULTS

Our search strategy resulted in the retrieval of 55 eligible studies reporting the prevalence of marine T. gondii infection. The highest prevalence belonged to mustelids (sea otter) with 54.8% (95% CI 34.21-74.57) and cetaceans (whale, dolphin, and porpoise) with 30.92% (95% CI 17.85-45.76). The microscopic agglutination test (MAT) with 41 records and indirect immunofluorescence assay (IFA) with 30 records were the most applied diagnostic techniques for T. gondii detection in marine species.

CONCLUSIONS

Our results indicated the geographic distribution and spectrum of infected marine species with T. gondii in different parts of the world. The spread of T. gondii among marine animals can affect the health of humans and other animals; in addition, it is possible that marine mammals act as sentinels of environmental contamination, especially the parasites by consuming water or prey species.

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.

Toxoplasmosis among cancer patients undergoing chemotherapy: a population study based on the serological, molecular and epidemiological aspects

BACKGROUND

Toxoplasmosis is highly prevalent in northern Iran and immunocompromised individuals are more susceptible to this infection. The present study aimed to determine the seroprevalence, parasitism and genetic diversity of Toxoplasma gondii among patients with cancer undergoing chemotherapy in northern Iran.

METHODS

A total of 350 serum samples obtained from cancer patients were collected from laboratory centers in northern Iran. Immunodiagnosis and DNA detection were accomplished by ELISA and PCR. Thereafter, multiplex-nested PCR-restriction fragment length polymorphism was used for the genotyping of T. gondii.

RESULTS

In general, out of 350 patients, 264 (75.4%) and 9 (2.57%) cases were positive for anti-T. gondii IgG and IgM, respectively. Moreover, 19 (5.43%) samples contained T. gondii DNA. From 19 positive samples, 10 high-quality samples with sharp and non-smear bands were selected to determine the genotypes of T. gondii. Accordingly, the samples were classified as genotype #1 (type II clonal; n=4, 40%), genotype #2 (type III clonal; n=3, 30%), genotype #10 (type I clonal; n=2, 20%) and genotype #27 (type I variant; n=1, 10%).

CONCLUSIONS

As evidenced by the results, due to the high prevalence of T. gondii, cancer patients in northern Iran are at serious risk of severe toxoplasmosis and its complications. Therefore, oncologists need to regard this critical health problem as a matter requiring urgent attention.

The Potential Contribution of ABO, Lewis and Secretor Histo-Blood Group Carbohydrates in Infection by Toxoplasma gondii

The glycosyltransferases encoded by genes from the human ABO, Lewis, and Secretor histo-blood group systems synthesize part of the carbohydrate antigens in hematopoietic and non-hematopoietic tissues. The combined action of these glycosyltransferases strongly influences cell, tissue, mucosa, and exocrine secretion carbohydrate phenotypes, including those serving as habitat for mutualistic and pathogenic microorganisms. A set of reports investigated associations between Toxoplasma gondii infection and the ABO histo-blood group system, but the results are contradictory. As T. gondii uses the gastrointestinal tract as a route for infection, and in this organ, the expression of ABO, Lewis, and Secretor histo-blood group carbohydrates occurs, it is reasonable to suppose some biological relationship between them. This text reviewed association studies published in recent decades focusing on the potential contribution of the ABO, Lewis, and Secretor histo-blood group carbohydrates and infection by T. gondii.

The global status and genetic characterization of hydatidosis in camels (Camelus dromedarius): a systematic literature review with meta-analysis based on published papers

Hydatidosis is a potential zoonotic helminthic disease affecting a broad spectrum of mammals, including humans, worldwide. The current review was conducted to investigate the genotypic status and prevalence of hydatid disease in camels across the world. For the purpose of the study, the articles addressing the worldwide prevalence of hydatidosis in camels were searched in several English language databases. The search process resulted in the inclusion of 122 papers. Based on the data presented in the reviewed articles, the pooled prevalence of hydatid disease in camels across the world was measured at 23.75% (95% CI 20.15-27.55). Moreover, the subgroup analysis demonstrated significant differences in the overall prevalence of hydatidosis among camels based on year, geographic area, climate parameters, camel population, gender, infected organ, fertility rate of the cyst and laboratory diagnostic technique. Furthermore, the Echinococcus granulosus genotypes identified in camels with hydatidosis included G1, G2, G3, G1-G3, G5, G6, G7, G6-G7 and G6-G10, with G6 being the most common genotype throughout the world. The data obtained from the current study are central to the better conceptualization of the biological and epidemiological characteristics of E. granulosus s.l. genotypes around the world, which can be helpful in the planning and adoption of more comprehensive control strategies.

Toxoplasma gondii infection as a potential risk for chronic liver diseases: A systematic review and meta-analysis

Toxoplasma gondii, the etiological agent of toxoplasmosis, can cause serious public health problems. Although Toxoplasma gondii tends more to neurotropic and ocular organs, some existing evidence suggest that this disease might induce serious pathological effects on liver. Hence, this study aimed to evaluate the relationship between chronic liver diseases and toxoplasmosis. Meanwhile, it attempted to assess whether patients with toxoplasmosis are susceptible to chronic liver diseases. To achieve this aim, the published studies related to the subject were systematically searched in five major electronic databases between the January 1, 1950 and October 1, 2019. The meta-analysis was carried out using the StatsDirect statistical software and a p-value less than 0.05 was considered significant for any test. Out of 691 identified studies, 10 studies met our inclusion criteria and entered this systematic review. The pooled prevalence rates of Toxoplasma gondii in patients with liver diseases (35.97%; 95% CI: 28.38-43.93) were higher than those in the control group (18.24%; 95% CI: 13.85-23.09). The meta-analysis indicated that the common Odd Ratio by a random effect model was 2.7 (95% CI: 2.30-3.24), revealing a significant association between chronic liver diseases and anti-Toxoplasma IgG antibody. The results of this systematic review confirmed the positive connection between toxoplasmosis and chronic liver diseases. Nonetheless, more studies are needed to clarify the detailed association between these diseases.

Increased Risk of Toxoplasma gondii Infection in Patients with Colorectal Cancer in Eastern China: Seroprevalence, Risk Factors, and a Case-Control Study

The aim of this study was to explore the epidemiology of Toxoplasma gondii infection in patients with colorectal cancer (CRC) in eastern China. Therefore, 287 primary CRC patients and 287 age-matched healthy control subjects were recruited to estimate the seroprevalence of T. gondii and identify the risk factors of infection. Enzyme-linked immunoassays were used to test for anti-T. gondii immunoglobulin G (IgG) and IgM antibodies. Forty-six (16%) samples were positive for anti-T. gondii IgG antibodies in patients with CRC, compared with 26 (9.1%) in the healthy controls, a significant difference (P = 0.007). By contrast, eight (2.8%) patients tested positive for T. gondii IgM antibodies, compared with three (1.1%) in the controls, a difference that was not significant (P = 0.13). Multivariable backward stepwise logistic regression analysis revealed that a rural residence (OR 2.83; 95% CI 1.15–7.01; P = 0.024) and treatment with chemotherapy (OR 2.16; 95% CI 1.02–4.57; P = 0.045) were risk factors for T. gondii infection in patients with CRC. Thus, T. gondii infection is serious in patients with CRC, and a rural residence and treatment with chemotherapy are independent risk factors for infection by this parasite. Therefore, medical professionals should be aware of this pathogen in patients with CRC, and the causes of T. gondii infection in these patients need to be explored further.

Sarcocystosis in Ruminants of Iran, as Neglected Food-Borne Disease: A Systematic Review and Meta-analysis

PURPOSE

Sarcocystis is a zoonotic parasitic pathogen which endangers the safety of meat and meat products. This systematic review and meta-analysis aimed to evaluate the prevalence rate and status of Sarcocystis spp. in ruminants as important food sources in Iran.

METHODS

Data were collected from papers indexed in five English language electronic databases (PubMed, Scopus, Web of Science, Science Direct, and Google Scholar) and four Persian electronic databases (IranMedex, SID, IranDoc, and Magiran) from January to April 2019. Papers were selected based on inclusion criteria. Data analysis was performed in StatsDirect statistical software, version 2.7.2.

RESULTS

The searching process resulted in the identification of 73 studies. Data analyses revealed that the total prevalence (95% confidence intervals) of Sarcocystis spp. in Iranian ruminants was 74.40% (64.01-83.56). In addition, a significant association was also observed between sarcocystosis infection in Iranian ruminants and year, host, location, and diagnostic technique (P < 0.001).

CONCLUSIONS

According to our data, the prevalence of Sarcocystis infection in ruminants is relatively high. High pathogenicity of some Sarcocystis spp. and the negative impact that the spread of some parasites among ruminants can have on human and animal health necessitate the direction of more attention toward monitoring, controlling, and preventing sarcocystosis.

Association between Toxoplasma gondii exposure and hematological malignancies: A systematic review and meta-analysis

The possible association between Toxoplasma gondii infection and hematological malignancies has been suggested by several studies. The current systematic review and meta-analysis was directed to further understand this relationship. In the present study, five electronic databases were reviewed for T. gondii infection in patients with blood cancer. The random effects model and 95% confidence intervals (CI) were used to determine the overall odds ratio (OR). Heterogeneity was deliberate with Cochran's Q test and I² statistic. In total, 13 studies including 1504 patients with hematological neoplasia and 2622 subjects without any malignancies were included in this meta-analysis. Overall, 324 patients with blood cancer and 391 subjects without any malignancies were exposed to Toxoplasma infection. The pooled random effect favored a statistically significant increased risk of T. gondii infection in patients with hematological neoplasia compared with non-cancer individuals [OR = 2.43; 95% CI: 1.49-3.97; χ2 = 49.7, I² = 75.9%, P = 0.00]. Also, significant pooled ORs of positive association were observed for studies which measured anti- Toxoplasma antibodies (IgG) [OR = 2.66; 95% CI: 1.46-4.83; χ2 = 40.3; I² = 82.6%, P = 0.00]. T-value and P-value were obtained 0.20 and 0.85 by Harbords modified regression test. This meta-analysis demonstrates that toxoplasmosis may be associated with an elevated risk of hematological malignancies. Also, it has found that immunoglobulin class and types of blood cancer are the specific sources of heterogeneity. Additional studies should be performed to examine the impact of T. gondii infection in the onset or development of hematologic neoplasms in the future.

Seroprevalence of Neospora caninum Infection in Dog Population Worldwide: A Systematic Review and Meta-analysis

PURPOSE

Neospora caninum is an obligate intracellular apicomplexan protozoan that causes neurological disorders in dogs. This systematic review and meta-analysis targeted at evaluating the worldwide seroprevalence rate of N. caninum in dogs.

METHODS

Five electronic databases, including PubMed, Scopus, Web of Science, Science Direct, and Google Scholar, until December 2018 were thoroughly searched for relevant English language articles. Papers were selected based on inclusion criteria. Data were analyzed in StatsDirect statistical software (version 2.7.9).

RESULTS

The searching process yielded a total number of 156 papers. The total prevalence (95% confidence intervals) of N. caninum infection in dog population worldwide was measured as 17.14% in data analyses (15.25-19.10). In addition, a significant association was also detected between neosporosis infection in dogs and continent, country, year, WHO regions, sample size and diagnostic method (P < 0.001).

CONCLUSION

Dogs are a matter of concern to public health officials as a source of N. caninum infection. Therefore, it is of paramount importance to provide comprehensive data and systematically analyze the prevalence of N. caninum infection in dogs. Accordingly, it is recommended that researchers carry out further studies to prevent and control neosporosis among dog population worldwide.

The global status of Dirofilaria immitis in dogs: a systematic review and meta-analysis based on published articles

Dirofilaria immitis is a parasitic filarial nematode responsible for heartworm disease in domestic as well as wild canines and felines and pulmonary or cutaneous infections in humans. This systematic review and meta-analysis aimed to evaluate the status of D. immitis in dogs based on available literature. Four English language databases (ISI Web of Science, Scopus, PubMed and Science Direct) containing data on D. immitis prevalence in dogs were thoroughly searched resulting in the inclusion of 193 studies. The findings revealed that the pooled and weighted prevalence of D. immitis infection in dog population based on published papers throughout the world was 10.91% (95% CI=10.18-11.65). In addition, subgroup analysis based on meta-regression revealed that a significant difference between the pooled and weighted prevalence of D. immitis in dogs and country (β =0.14, P=0.049). Given the relatively high prevalence of D. immitis infection in dogs and its adverse effects, it is suggested that to perform more research on the prevention and control of dirofilariasis infection in dogs worldwide.

A systematic review and meta-analysis of the genetic characterization of human echinococcosis in Iran, an endemic country

Human echinococcosis is an infectious disease caused by tapeworms belonging to the species Echinococcus. This parasite has a worldwide distribution and is considered a neglected tropical disease by the World Health Organization. Due to the diversity of Echinococcus spp. hosts, as well as variation in geographical, climatic, and socio-ethnic conditions, the question of the strains or genotypes of Echinococcus spp. that are involved in human infections is important. The aim of this study was to provide a summary of the available data on genotypes of Echinococcus obtained from the Iranian population. Four international databases (PubMed, Scopus, Science Direct, and Web of Science) and 4 Persian databases (Magiran, Scientific Information Database, Iran Medex, and IranDoc) were searched for cross-sectional studies that reported the genotypes of Echinococcus spp. in human echinococcosis cases using molecular methods in Iran through July 2018. The Newcastle-Ottawa Scale was used to assess the quality of the selected studies. A total of 559 cases of human cystic echinococcosis were reported in the 21 included articles. The majority of cases belonged to genotype G1 (89.2%; 95% confidence interval [CI], 80.1 to 95.8), genotype G6 (8.2%; 95% CI, 2.8 to 15.9), and genotype G3 (2.3%; 95% CI, 1.1 to 3.9). Since genotype G1 of Echinococcus appears to be the most prevalent genotype affecting humans in Iran, disease control initiatives aimed at sheep intermediate hosts may be the most beneficial. In addition, educational programs and serological screening in individuals may help reduce the national impact of the disease.

Frequency and genetic diversity of Blastocystis subtypes among patients attending to health centers in Mazandaran, northern Iran

Blastocystis hominis is a common intestinal protozoan with global distribution. The prevalence of B. hominis is extremely diverse in different countries. Molecular studies show that there is a great deal of genetic variation in the Blastocystis parasite isolated from humans and animals. Therefore, this study was conducted to determine B. hominis genotypes in patients attending to health centers of Sari, Mazandaran Province, north of Iran. 420 fecal specimens were collected from individuals in health centers of Sari from April to December 2017. The samples were examined by direct methods, parasite test (formalin ether) and Giemsa staining. In order to determine the genotypes of Blastocystis parasite, all positive samples in direct methods were tested by PCR using SSU rDNA gene. Eventually, seven positive molecular samples were sequenced and recorded in the gene bank. The phylogenetic analysis was done by drawing a gene tree using the neighbor-joining procedure. B. hominis was detected in 60 stool specimens by microscopic method. All these 60 samples were positive by PCR and the bands 310 bp were observed. According to the phylogenetic tree, it was revealed that B. hominis isolates of Mazandaran Province are more similar to subtype ST3 (ST type) that reported in Khorramabad in Lorestan Province (West of Iran). The present study showed that, like most studies, ST3 is the dominant genotype of protozoan in Sari. Improvement of public health awareness, relative improvement in environmental health, urban wastewater treatment, proper clothing coverage and the use of gloves during dealing with livestock and the use of domestic water treatment devices can reduce the Blastocystis infection in this area.