Parasite Epidemiology and Control最新文献

Background

Fruits and vegetables are very important for human diet as they provide all the nutrients needed to be healthy with just a daily-recommended intake of 400 to 600 mg. However, they constitute one of the major sources of human infectious agents. Thus monitoring of the microbial contaminants of the fruits and vegetables is very crucial for human safety.

Method

A cross sectional study was conducted on fruits and vegetables in four markets (Mfoundi, Mokolo, Huitième and Acacia) of the Yaoundé city from October 2020 to March 2021. In all, 528 samples were purchased (carrots, cucumbers, cabbages, lettuces, leeks, green beans, okra, celeries, pepper, green peppers and tomatoes) and processed for infective agents using the centrifugation methods (Formalin, distilled and saline water). Seventy-four (74) soil/water samples collected from the sale environment were analysed using the same technics.

Results

Overall, 149/528 (28.21%) were contaminated by at least one infective agent: 130 (24.62%) and 19 (3.6%) having one and two pathogen species respectively. Vegetables had high contamination rate (22.34%) than fruits (5.87%). Lettuce (52.08%), carrot (41.66%) and cabbage (35.41%), were the most contaminated while okra was the least (6.25%). Candida spp. (14.01%) and larva of Strongyloides stercoralis (7.76%) were more observed while Hookworms (1.13%) was the least. Frequency of Strongyloides stercoralis (p = 0.001) and Candida spp. (p = 0.01) were statistically high than other pathogens. Contamination rates were similar for washed (27.65%) and unwashed (28.78%) samples before sale. Candida spp. (p = 0.001), Strongyloides stercoralis (p = 0.01) and Entamoeba histolytica/dispar (p = 0.017) showed significant contamination rates by month. Contamination trends were high in the rainy season (42.6%) than the dry season (15.1%). Correlation between environment and products sold revealed same pathogens in both cases.

Conclusion

The study highlights that the sale environment and products constitute potential source of microbial contamination. These data raised the concern of stakeholders about health risk related to vegetables and fruits sold in some local markets in Cameroon. Thus the necessity for them to development more appropriate policies on the surveillance of sale environment and on the management of these products during the different process phases by the population.

Background

Schistosomiasis is endemic in Cameroon and continues to cause serious public health problems, especially among populations in rural areas. This study aimed at determining the prevalence and risk factors of urinary and intestinal schistosomiasis in Manjo.

Method

A cross-sectional study was conducted in the city of Manjo in 2020. Stool and urine samples were collected from 400 participants. These stool and urine samples were examined by the Kato Katz, and centrifugation methods respectively.

Results

The results obtained showed an overall prevalence of 6.25%, with 5% and 1.25% for S. mansoni and S. haematobium respectively. A significant difference (p < 0.05) was revealed among occupations, age groups, neighborhood, water usage, educational level, knowledge of the disease meanwhile no significant difference was observed between gender and occupation according to prevalence. The most infected ages were] 50-; + [and]20–35] with 13.36% and 11.86% respectively. S. haematobium revealed a low infection intensity while S. mansoni showed moderate infection intensity. The mean parasite load for S. haematobium was 6 ± 3.225 Eggs/10 ml in females and 7 ± 4.243 Eggs/10 ml for males; while the mean parasitic load in S. mansoni was 180 ± 142.441 Epg in females and 146.67 ± 82.286 Epg in males.

Conclusion

Manjo can be classified as a low endemic area with a prevalence rate of 6.25% and species observed were S. haematobium and S. mansoni. Also, risk factors where observed including the use of water from the river for domestic purposes. Therefore, the intensification of health education campaigns among the population would delay the development of this disease in the locality.

Currently, parasitic infections are one of the important health problems in the world, especially in developing countries. This study aims to investigate intestinal parasites with an emphasis on molecular identification through the analysis of mitochondrial COX1 and ITS2 gene sequences of Strongyloides stercoralis (S. stercoralis) and Trichostrongylus spp. in north of Iran. Five hundred forty stool samples were collected from medical diagnostic laboratories affiliated with Mazandaran University of Medical Sciences in Sari city, north of Iran. First, all the samples were examined using direct smear, formalin-ether sedimentation, and trichrome staining technique. Suspected samples of Strongyloides larvae were cultured in agar plate. Then, DNA was extracted from samples containing Trichostrongylus spp. eggs and Strongyloides larvae. To amplify DNA, PCR was performed and the samples with a sharp band in electrophoresis were sequenced by Sanger method. Overall, the prevalence of parasitic infections in the study population was 5.4%. The highest and the lowest level of infection was observed with Trichostrongylus spp. and S. stercoralis at 3% and 0.2%, respectively. No traces of live Strongyloides larvae were seen in the culture medium of the agar plate. The six isolates obtained from the amplification of the ITS2 gene of Trichostrongylus spp. were sequenced, all of which were Trichostrongylus colubriformis. The sequencing results of COX1 gene indicated S. stercoralis. In the present study, the prevalence of intestinal parasitic infections in north of Iran has relatively decreased that its main reason can be due to the coronavirus epidemic and compliance with health principles. However, the prevalence of Trichostrongylus parasite was relatively high that it requires special attention to apply appropriate control and treatment strategies in this field.

Background

Porcine cysticercosis is an endemic parasitic zoonosis in many developing countries. The objective of this study was to estimate the seroprevalence of porcine cysticercosis in traditional pig farms in the departments of Dabou, Aboisso and Agboville.

Methods

Blood samples were taken from pigs and analyzed by ELISA (IgG) and western blot. Data on farming practices and pig characteristics were collected. Multivariate logistic regression models were constructed to identify risk factors.

Results

A total of 668 pigs were sampled from 116 farms and 639 samples were analyzed. The seroprevalence of cysticercosis was estimated at 13.2%. Overweight [OR = 2.6; 95%CI (1.3–4.9)] and fat pigs [OR = 2.3; 95%CI (1.0–4.8)] were twice as likely to be seropositive for cysticercosis. This risk was increased in farms using well water for drinking [OR = 2.5; 95%CI (1.0–6.3)] as well as those reporting veterinary care of the animals (OR = 2.9; 95%CI (1.2–7.3)).

Conclusions

This study demonstrated the circulation of Taenia solium in pig farms in southern Côte d'Ivoire.

Background

Acanthamoeba spp. is opportunistic amoeba that resides in water, soil, and air. Some pathogenic genotypes of the genus of Acanthamoeba can cause granulomatous amoebic encephalitis (GAE) in people with a defective immune system. The parasite can also cause Acanthamoeba keratitis (AK) among contact lens users. This study was conducted to isolate and identify the Acanthamoeba genotypes in water resources in Lorestan province, western Iran.

Methods

Collected 72 water samples from surface and groundwater (springs and aqueducts) in Lorestan province. Samples were filtered and cultured in non-nutrient 1.5% agar medium covered with Escherichia coli (E. coli) at 25 °C. DNA extraction was done and the PCR reaction was performed to detect the Acanthamoeba spp. The positive PCR products were sequenced to determine the genotypes of Acanthamoeba.

Results

Out of 72 examined water samples, 23.61% were positive for Acanthamoeba sp. by PCR. From PCR-positive samples, 8 (47.05%) samples were T4 genotypes and others were other Acanthamoeba genotypes (T1-T23). Therefore, approximately half of the genotypes belong to the pathogenic T4 genotype.

Conclusions

The water examined samples in western provinces of Iran have the potential risk factor for public health. Therefore, the efforts of healthcare providers are needed to identify, train, and prevention from human infections.

Background

Parasitic infections are among the most common diseases worldwide, and enterobiasis is a well-known type of parasitic infection in children. Given the existence of several reports on the prevalence of Enterobius vermicularis in different provinces of Iran and the heterogeneity of the reported prevalence data, this study aims to investigate the overall prevalence of Enterobius vermicularis among children in Iran through a systematic review and meta-analysis.

Methods

This systematic review and meta-analysis study involved a comprehensive search of several databases, including PubMed, ScienceDirect, SID, and Google Scholar, focusing on cross-sectional studies that examined the prevalence of Enterobius vermicularis infection in Iranian children. The identified studies were entered into the EndNote software for review. The quality of observational studies was evaluated using the STROBE checklist. The information extracted from the studies was entered into the Comprehensive Meta-analysis (CMA, Version 2) software. Heterogeneity among the studies was analyzed using the I² test, and publication bias was assessed using the Egger test and funnel plot.

Results

A total of 51 studies, with a sample size of 46,070 children, were included in the review. Using the random effects method, the overall prevalence of Enterobius vermicularis among children in Iran was determined to be 6.7% (95%CI: 5.2–8.6). The review of the factors affecting study heterogeneity and sample size indicated that as sample size increased, the prevalence of Enterobius vermicularis among children in Iran also increased (p = 0.578). Additionally, with an increase in the year of conducting the studies, the prevalence of Enterobius vermicularis among children in Iran decreased (p < 0.05).

Conclusion

The findings of this study show a relatively high prevalence of Enterobius vermicularis among children in Iran. We recommend health policymakers recognize the significance of this issue and take necessary measures to reduce the incidence of this infectious agent in children, implementing more effective preventive measures through mass media and educational campaigns.

Bovine fasciolosis caused by Fasciola hepatica and Fasciola gigantica, is a neglected tropical snail-borne trematode disease of cattle that poses an adverse effect on animals' health culminating in economic damage. Cross-sectional investigation on coprological and postmortem assessment and economic significance of bovine fasciolosis in cattle slaughtered at Tarcha Municipal Abattoir, Southern Ethiopia through simple random sampling techniques was conducted from December 2020 to August 2021. Out of 384 cattle examined, 20.3% and 29.94% were found harboring Fasciola through coprological examination and postmortem examination respectively. The leading cause of fasciolosis in the study area was Fasciola gigantica (53.9%) as compared to F. hepatica (46.1%). The investigation revealed that the sex, origin, and body condition of the cattle has a statistically significant effect on the prevalence of bovine fasciolosis. The odds of male animals infested with fasciolosis were 2.25 times higher than female cattle and those of poor body-conditioned cattle were three times higher than cattle with good body condition. In postmortem examination, an average of 6 flukes were found in a single infested liver and the mean fluke count was (10 ± 1.97) in severely infested livers while in lightly infested livers (3± 1.79). Considering postmortem examination as the gold standard for diagnosis of fasciolosis, the sensitivity of the direct sedimentation technique was found to be 68% and the specificity 100% with substantial agreement (k = 0.74) between the two methods. The estimated yearly direct financial losses incurred owing to fasciolosis was around 2,227,536 2, Birr (47,945.24 USD). Thus, bovine fasciolosis is one of the economically important animal diseases in the study area, which necessitates integrated control measures to tackle its effect on animal health and subsequent economic impact.

Co-infection of COVID-19 with other diseases increases the challenges related to its treatment management. COVID-19 co-infection with parasites is studied with low frequency. Here, we systematically reviewed the cases of parasitic disease co-infection with COVID-19. All articles on COVID-19 co-infected with parasites (protozoa, helminths, and ectoparasites), were screened through defined inclusion/exclusion criteria.

Of 2190 records, 35 studies remained for data extraction. The majority of studies were about COVID-19 co-infected with malaria, followed by strongyloidiasis, amoebiasis, chagas, filariasis, giardiasis, leishmaniasis, lophomoniasis, myiasis, and toxoplasmosis. No or low manifestation differences were reported between the co-infected cases and naïve COVID-19 or naïve parasitic disease.

Although there was a relatively low number of reports on parasitic diseases-COVID-19 co-infection, COVID-19 and some parasitic diseases have overlapping symptoms and also COVID-19 conditions and treatment regimens may cause some parasites re-emergence, relapse, or re-activation. Therefore, more attention should be paid to the on-time diagnosis of COVID-19 and the co-infected parasites.

The aim of the present study was to determine the molecular characteristics of Echinococcus granulosus sensu lato from faecal samples of dogs and the hydatid cyst from liver of bovine, camel, cattle, and sheep and the immunodiagnosis of Hydatid cyst in human sera samples from the Gaza Strip, in Palestine. A total of 38 faecal samples were collected near farms and local markets where stray dogs were grouping there. Post-slaughtering, the livers of the bovine, camel, cattle, and sheep were examined for cysts. Where 30 suspected hydatid cysts were collected, the number and size of cysts in each liver were recorded. For serology, 23 sera specimens were collected from farmers within the Gaza Strip. According to hospital records in Gaza, 12 patients had attended three different hospitals and had tested positive for hydatid cyst/cystic echinococcosis by CT scans and histopathology. ELISA results from the 23 human patients showed that 3/23 (13%) tested positive for hydatid disease. Of the 30 bovine and cattle harboring cysts, 14/30 (46.6%) were positive for hydatid cyst/cystic echinococcosis of which 23 (76.7%) were males and 7 (23.3%) were females. The present study shows that 6/38 (15.7%) were positive for E. granulosus sensu lato from faecal analysis in dogs. Subsequent sequencing of both dogs and cattle confirmed infection by the G1 strain. The cattle/dog strain (G1) of E.granulosus sensu lato suggests that this infection is cosmopolitan in its distribution. It is concluded that the detection of hydatid cyst/cystic echinococcosis in the examined hosts either human or animals should be considered among physicians and a large sample size is recommended in future research.

Cryptosporidiosis is a zoonotic disease caused by Cryptosporidium. The disease poses a public and veterinary health problem worldwide. A deterministic model and its corresponding continuous time Markov chain (CTMC) stochastic model are developed and analyzed to investigate cryptosporidiosis transmission dynamics in humans and cattle. The basic reproduction number $R_0$ for the deterministic model and stochastic threshold for the CTMC stochastic model are computed by the next generation matrix method and multitype branching process, respectively. The normalized forward sensitivity index method is used to determine the sensitivity index for each parameter in $R_0$. Per capita birth rate of cattle, the rate of cattle to acquire cryptosporidiosis infection from the environment and the rate at which infected cattle shed Cryptosporidium oocysts in the environment play an important role in the persistence of the disease whereas Cryptosporidium oocysts natural death rate, cattle recovery rate and cattle natural death rate are most negative sensitive parameters in the dynamics of cryptosporidiosis. Numerical results for CTMC stochastic model show that the likelihood of cryptosporidiosis extinction is high when it arises from an infected human. However, there is a major outbreak if cryptosporidiosis emerges either from infected cattle or from Cryptosporidium oocysts in the environment or when it emerges from all three infectious compartments. Therefore to control the disease, control measures should focus on maintaining personal and cattle farm hygiene and decontaminating the environment to destroy Cryptosporidium oocysts.