OBJECTIVE: To analyze the quality of blood smear examinations for malaria parasites in Chenzhou City, so as to provide insights into sustainable consolidation of malaria elimination achievements. METHODS: All positive blood smears from fever patients were irregularly sampled from each county (district) of Chenzhou City from 2018 to 2022 and reexamined, and no less than 3% negative blood smears were reexamined. The preparation, dyeing, cleanliness and microscopic examination results of blood smear were reexamined, and the quality of blood smear reexaminations was assessed using a descriptive statistical method. RESULTS: A total of 13 625 fever patients received blood smear examinations for malaria parasites in Chenzhou City from 2018 to 2022, of which 21 were positive and 13 604 were negative; 687 blood samples were reviewed, and the percentage of negative blood smear reexaminations was 4.90% (666/13 604), with a 63.51% rate of qualified negative blood smears preparation, a 67.87% rate of qualified dyeing and a 76.13% rate of qualified cleanliness, and no missing diagnosis found. There were 21 positive blood smears reexamined, and the proportions of qualified blood smears preparation, dyeing and cleanliness were all 85.71%, with 2 smears mistaking Plasmodium species (9.52%). The percentage of qualified negative blood smears preparation was 51.41% in 2022, which reduced by 31.61% in relative to that (75.17%) in 2019 (χ² = 9.033, P < 0.05), and the percentage of qualified negative blood smears dyeing was 60.19% in 2022, which reduced by 28.82% in relative to that (84.56%) in 2019 (χ² = 19.498, P < 0.05), while the percentage of qualified negative blood smears cleanliness was 62.96% in 2022, which reduced by 28.93% in relative to that (88.59%) in 2019 (χ² = 23.826, P < 0.001). In addition, there were no significant differences in the proportion of qualified negative blood smears preparation (χ² = 0.260, P > 0.05) or dyeing (χ² = 1.094, P > 0.05) among the three years, while a significant difference was detected in the percentage of qualified negative blood smears cleanliness (χ² = 12.175, P < 0.05). CONCLUSIONS No missing diagnosis was seen in blood smear examinations for malaria parasites among fever patients in Chenzhou City after malaria elimination; however, there were reductions in proportions of qualified blood smears preparation, dyeing and cleanliness. Quality control of blood smear examinations is recommended to be reinforced in key regions of Chenzhou City.
Animals ; Humans ; Parasites ; Malaria/prevention & control* ; Plasmodium ; Fever ; Microscopy

Parasite-derived non-coding RNAs (ncRNAs) not only contribute to life activities of parasites, and microRNA (miRNA), long non-coding RNA (lncRNA), and circular RNA (circRNA) may generate a competitive endogenous RNA (ceRNA) regulatory network with host miRNAs and mRNAs via extracellular vesicles, thereby participating in infection and pathogenic processes. This article presents an overview of characterizing ncRNAs derived from parasites and the cross-species regulatory role of parasite-derived ncRNAs in host gene expression and its underlying mechanisms.
Animals ; Parasites ; Gene Regulatory Networks ; MicroRNAs/metabolism* ; RNA, Messenger/genetics* ; RNA, Circular/genetics* ; RNA, Competitive Endogenous

Introduction: Dioctophyma renale, also known as the “giant kidney” worm is the largest nematode that infects mammals. Most commonly, it infects dogs and only a few cases of human infestation have been reported. Case Presentation: In this case, we present a 71-year-old male with a history of right flank pain, painless hematuria, obstructive urinary symptoms and occasional passage of a long red meat-like structure via urethra. Previous ultrasonography revealed a renal mass that was interpreted as renal malignancy. Patient was advised radical nephrectomy with biopsy; however, he was lost to follow up. After 8 years, he again presented with a 2-month history of right flank pain, gross hematuria, unintentional weight loss and obstructive urinary symptoms. He was admitted to our institution and laboratory findings revealed microcytic hypochromic anemia. Ultrasound showed a focal bulge in the superior wall of the urinary bladder and an enlarged right kidney with a large heterogeneous solid structure. Insertion of a foley catheter relieved the urinary obstruction and there was noted passage of a single roundworm measuring 55 cm by 0.32 cm. The specimen was sent for histopathology and microscopic examination revealed a necrotic body of a roundworm consistent with Dioctophyma renale. Case Discussion The clinical manifestations of D. renale infection are non-specific and the diagnosis can be a challenge as it commonly mimics renal malignancy and other intra-abdominal tumors. The diagnosis is often an incidental finding of the parasite on necropsy or by finding ova in the urine. The clinical findings of painless hematuria, unintentional weight loss and an ultrasound finding of renal mass usually point toward the diagnosis of renal cell carcinoma. As we present this case, it will be highlighted that such signs and symptoms, such as painless hematuria, unintentional weight loss and ultrasound finding of a renal mass, can also be found in patients with rare human parasitism from Dioctophyma renale.
Parasites ; Dioctophymatoidea ; Carcinoma ; Kidney

Hydatid disease is a zoonotic infection in humans. The disease is endemic in some parts of the world, including Africa, Australia, and Asia, where cattle grazing is common; the disease is spread by an enteric route following the consumption of food contaminated with the eggs of the parasite. Failure to identify this parasite results in delayed diagnosis and increased morbidity to the patient. Upon diagnosis, every possible step should be taken, both surgical and medical, to prevent anaphylactic reactions from the cystic fluid. Postsurgical long-term follow up along with periodical ultrasonography of the liver and computed tomography scan of the abdomen is essential to rule out possible recurrence.
Abdomen ; Africa ; Anaphylaxis ; Animals ; Asia ; Australia ; Cattle ; Delayed Diagnosis ; Diagnosis ; Echinococcosis ; Eggs ; Follow-Up Studies ; Humans ; Liver ; Ovum ; Parasites ; Recurrence ; Ultrasonography ; Zoonoses

OBJECTIVES: To determine the prevalence and risk factors associated with intestinal parasites in the population of San Juan Cosala, Jalisco, Mexico. METHODS: A total of 277 samples from 104 participants were analysed using direct smear, flotation, formaldehyde/ethyl acetate, and modified Kinyoun’s acid-fast stain methods. The Graham method was applied only for samples from children under 12 years of age for the diagnosis of Enterobius vermicularis. RESULTS: The prevalence of parasite infections in the study population was 77.9% including: Entamoeba histolytica/E. dispar/E. moshkovskii/E. bangladeshi (37.5%), Giardia intestinalis (11.5%); commensals: Endolimax nana (44.2%), Entamoeba coli (27.9%), Chilomastix mesnili (6.7%) and Iodamoeba bütschlii, (2.9%); emerging intestinal protozoans: Blastocystis spp. (49%), Cryptosporidium spp. (7.7%) and Cyclospora cayetanensis (2.9%); and helminths: Enterobius vermicularis (18.3%) and Ascaris lumbricoides (5.8%). The results also showed that 58.64% of the studied population presented polyparasitism. A significant association was found between protozoan infections and housewives, and houses that were not built with concrete ceilings, brick walls and cement floors (p < 0.05). CONCLUSION: Polyparasitism was observed in over half the study population. The most prevalent parasite was Blastocystis spp, whilst the prevalence of helminths was less than that of protozoans. The risk factors for infection to intestinal parasites were being a housewife and not having solid brick, cement and concrete materials for house construction.
Adult ; Ascaris lumbricoides ; Blastocystis ; Child ; Cryptosporidium ; Cyclospora ; Diagnosis ; Endolimax ; Entamoeba ; Enterobius ; Giardia lamblia ; Helminths ; Humans ; Methods ; Mexico ; Parasites ; Prevalence ; Protozoan Infections ; Retortamonadidae ; Risk Factors

Trichomoniasis is a common sexually transmitted infection caused by Trichomonas vaginalis, which actually does not exist a vaccine for control or prevention. Thus, the identification of new and potent immunogens in T. vaginalis, which can contribute to the development of a vaccine against this parasite, is necessary. Therefore, the aim of this work was to evaluate the potential of a recombinant Transient Receptor Potential-like channel of T. vaginalis (TvTRPV), as a promising immunogen in BALB/c mice. First, TvTRPV was cloned and expressed as a recombinant protein in Escherichia coli BL21 cells and purified by nickel affinity. Next, BALB/c mice were immunized and the antibody levels in mice serum and cytokines from the supernatant of macrophages and from co-culture systems were evaluated. Recombinant TvTRPV triggered high levels of specific total IgG in sera from the immunized mice. Also, a statistically significant increase of cytokines: IL-1β, IL-6, and TNF-α after stimulation with the corresponding antigens in vitro, was identified. Moreover, co-cultures using CD4⁺ T cells from immunized mice were able to identify higher levels of IL-10 and IFN-γ. These results were useful to validate the immunogenicity of TvTRPV in BALB/c mice, where IL-10-IFN-γ-secreting cells could play a role in infection control, supporting the potential of TvTRPV as a promising target for vaccine against T. vaginalis.
Animals ; Calcium ; Clone Cells ; Coculture Techniques ; Cytokines ; Escherichia coli ; Immunoglobulin G ; In Vitro Techniques ; Infection Control ; Interleukin-10 ; Interleukin-6 ; Macrophages ; Mice ; Nickel ; Parasites ; Sexually Transmitted Diseases ; T-Lymphocytes ; Trichomonas vaginalis ; Trichomonas

Toxoplasmosis is a cosmopolitan zoonotic infection, caused by a unicellular protozoan parasite known as Toxoplasma gondii that belongs to the phylum Apicomplexa. It is estimated that over one-third of the world's population has been exposed and are latently infected with the parasite. In humans, toxoplasmosis is predominantly asymptomatic in immunocompetent persons, while among immunocompromised individuals may be cause severe and progressive complications with poor prognosis. Moreover, seronegative pregnant mothers are other risk groups for acquiring the infection. The life cycle of T. gondii is very complex, indicating the presence of a plurality of antigenic epitopes. Despite of great advances, recognize and construct novel vaccines for prevent and control of toxoplasmosis in both humans and animals is still remains a great challenge for researchers to select potential protein sequences as the ideal antigens. Notably, in several past years, constant efforts of researchers have made considerable advances to elucidate the different aspects of the cell and molecular biology of T. gondii mainly on microneme antigens, dense granule antigens, surface antigens, and rhoptry proteins (ROP). These attempts thereby provided great impetus to the present focus on vaccine development, according to the defined subcellular components of the parasite. Although, currently there is no commercial vaccine for use in humans. Among the main identified T. gondii antigens, ROPs appear as a putative vaccine candidate that are vital for invasion procedure as well as survival within host cells. Overall, it is estimated that they occupy about 1%–30% of the total parasite cell volume. In this review, we have summarized the recent progress of ROP-based vaccine development through various strategies from DNA vaccines, epitope or multi epitope-based vaccines, recombinant protein vaccines to vaccines based on live-attenuated vectors and prime-boost strategies in different mouse models.
Animals ; Antigens, Surface ; Apicomplexa ; Cell Size ; Epitopes ; Humans ; Immunization ; Life Cycle Stages ; Mice ; Molecular Biology ; Mothers ; Parasites ; Prognosis ; Toxoplasma* ; Toxoplasmosis ; Vaccines ; Vaccines, DNA ; Vaccines, Synthetic ; Zoonoses

Avian malaria is one of the most important general blood parasites of poultry in Southeast Asia. Plasmodium (P.) juxtanucleare causes avian malaria in wild and domestic fowl. This study aimed to identify and characterize the Plasmodium species infecting in Thai native fowl. Blood samples were collected for microscopic examination, followed by detection of the Plasmodium cox I gene by using PCR. Five of the 10 sampled fowl had the desired 588 base pair amplicons. Sequence analysis of the five amplicons indicated that the nucleotide and amino acid sequences were homologous to each other and were closely related (100% identity) to a P. juxtanucleare strain isolated in Japan (AB250415). Furthermore, the phylogenetic tree of the cox I gene showed that the P. juxtanucleare in this study were grouped together and clustered with the Japan strain. The presence of P. juxtanucleare described in this study is the first report of P. juxtanucleare in the Thai native fowl of Thailand.
Amino Acid Sequence ; Animals ; Asia, Southeastern ; Asian Continental Ancestry Group ; Base Pairing ; Cytochromes c ; Cytochromes ; Electron Transport Complex IV ; Humans ; Japan ; Malaria, Avian ; Parasites ; Plasmodium ; Polymerase Chain Reaction ; Poultry ; Sequence Analysis ; Thailand ; Trees

Rapid diagnostic tests (RDTs) for malaria using antibodies against pan-Plasmodium antigen lactate dehydrogenase (pLDH) are commonly used for malaria diagnosis. The level of malaria parasitemia determined by peripheral blood smears (PBS) correlates with the pLDH concentration in most cases. We report a case of malaria recurrence associated with false-negative RDT results. A 22-year-old male patient was admitted to the Armed Forces Capital Hospital with fever and chills, and was diagnosed with malaria infection. Four days after antimalarial treatment, these symptoms recurred. After admitting to our hospital, doxycycline was administered for 4 days. Even after administration of doxycycline, the malaria parasites in blood smears remained positive, but RDT showed negative results. Therefore, for patients receiving doxycycline, serial blood smear testing should be performed to exclude false-negative malaria RDT results.
Antibodies ; Arm ; Chills ; Diagnosis ; Diagnostic Tests, Routine ; Doxycycline ; Fever ; Humans ; L-Lactate Dehydrogenase ; Malaria ; Male ; Parasitemia ; Parasites ; Recurrence ; Young Adult

Simian malaria is a zoonotic disease caused by Plasmodium knowlesi infection. The common natural reservoir of the parasite is the macaque monkey and the vector is the Anopheles mosquito. Human cases of P. knowlesi infection has been reported in all South East Asian countries in the last decade, and it is currently the most common type of malaria seen in Malaysia and Brunei. Between 2007–2017, 73 cases of P. knowlesi infection were notified and confirmed to the Ministry of Health in Brunei. Of these, 15 cases (21%) were documented as work-related, and 28 other cases (38%) were classified as probably related to work (due to incomplete history). The occupations of those with probable and confirmed work related infections were border patrol officers, Armed Forces and security personnel, Department of Forestry officers, boatmen and researchers. The remaining cases classified as most likely not related to work were possibly acquired via peri-domestic transmission. The risk of this zoonotic infection extends to tourists and overseas visitors who have to travel to the jungle in the course of their work. It can be minimised with the recommended use of prophylaxis for those going on duty into the jungles, application of mosquito/insect repellants, and use of repellant impregnated uniforms and bed nets in jungle camp sites.
Anopheles ; Arm ; Asian Continental Ancestry Group ; Brunei ; Culicidae ; Forestry ; Haplorhini ; Humans ; Macaca ; Malaria ; Malaysia ; Occupations ; Parasites ; Plasmodium knowlesi ; Plasmodium ; Zoonoses