Acta Parasitologica最新文献

Purpose

Peptidyl-tRNA hydrolase (Pth), first described in Escherichia coli, is responsible for rescuing stalled ribosomes during peptidyl-tRNA “drop off”. Bacterial Pth has been widely studied, but the characterization of eukaryotic Pth remains a poorly researched field, especially in protozoan parasites. This work aimed to characterize Trypanosoma cruzi Pths and determine their localization.

Methods

Two open reading frames (ORFs) that may encode Pths were identified in the T. cruzi genome. Bioinformatics analysis was performed for each protein using conserved domain analysis and multiple alignment. ORFs were cloned into an expression vector, E. coli pth(Ts) competent cells were transformed, and thermosensitivity tests were performed. Recombinant proteins were expressed and purified to immunize rats and obtain polyclonal antibodies. Pull down and immunoprecipitation followed by mass spectrometry to verify the interactions.

Results

TcPth and TcPth2 have a conserved domain corresponding to the Pth2 superfamily. Multiple alignments with previously characterized amino acid sequences of Pths showed that they are unrelated to T. cruzi proteins, considering that conserved residues of catalytic importance are absent. TcPth was able to rescue the E. coli thermosensitive pth(Ts) mutation, but TcPth2 was not. TcPth2 interacts with reservosome proteins such as cysteine peptidase and endocytic pathway proteins.

Conclusion

The results suggest that TcPth and TcPth2 has a different function. This work represents the first in its area since the Pths of the T. cruzi were characterized and breaks ground for the characterization of Pths from other protozoan parasites.

Purpose

To investigate the seroprevalence and molecular characterization of Anaplasma parasites in mithun (Bos frontalis) and their tick vectors in Nagaland and Arunachal Pradesh, India using serological and molecular methods.

Methods

Mithun sera were screened for Anaplasma antibodies using a competitive ELISA targeting the MSP5 antigen. Blood samples and ticks collected from mithun were analyzed using PCR targeting the RNA polymerase subunit beta (rpoB) gene for Anaplasma species detection, followed by sequencing and phylogenetic analysis of positive samples.

Results

Serological testing detected Anaplasma antibodies in 11.90% (5/42) of tested mithun. PCR analysis of 358 mithun blood samples identified eight animals (2.23%) positive for A. marginale, with identity confirmed through sequencing and phylogenetic analysis. Among the collected ticks, Anaplasma was detected in one R. microplus specimen (1/340), while all Amblyomma spp. (n = 25) tested negative. Phylogenetic analysis of the rpoB gene sequences showed the mithun isolates clustering with A. marginale reference sequences from diverse regions.

Conclusion

This study provides the first documented evidence of A. marginale infection in mithun populations and associated ticks in Northeast India, supported by molecular, serological and phylogenetic analyses. The findings underscore the importance of multi-faceted diagnostic approaches, targeted vector control, and ongoing surveillance to address regional disease risks.

Purpose

Plasmodium inui is a type of malaria that is endemic in simian populations in Southeast Asia, primarily infecting nonhuman primates, one of which is Macaca fascicularis, or the long-tailed macaque. Plasmodium inui, a malaria parasite endemic to simian populations in Southeast Asia, predominantly targets non-human primates. The escalating rates of deforestation and urban expansion, which facilitate increased interactions between humans and primates, have intensified concerns regarding its zoonotic potential. Despite receiving comparatively less scholarly attention than P. knowlesi, P. inui is distinguished by its substantial strain diversity and capacity to infect various macaque species. This review investigates the potential for crossspecies transmission of P. inui to humans, concentrating on the regions of Indonesia and Southeast Asia.

Methods

We evaluate the ecological and epidemiological determinants influencing the distribution and transmission dynamics of P. inui among macaques while also considering the implications for human infection based on a literature review obtained from PubMed, Google Scholar, and Scopus.

Results

Although no documented human cases have emerged in Indonesia, cases in humans have only been detected in Malaysia and Thailand, the review underscores the zoonotic risk associated with P. inui, drawing comparisons to other simian malaria species that have successfully infiltrated human populations. The lack of systematic surveillance and detailed molecular investigations concerning P. inui in these regions accentuates the imperative for further scholarly inquiry.

Conclusion

This review emphasizes the need for ongoing monitoring and research to enhance the understanding of zoonotic threats associated with P. inui, and informs future public health initiatives in Southeast Asia through a comprehensive evaluation of the genetic diversity of the parasite and its potential implications for public health.

Purpose

Infection of macrophages is a mandatory step for Lesihmania to promote mammalian infection and the evaluation of parasites proliferating inside macrophages reveals important information about parasites virulence and leishmanicidal drugs. Here we compare macrophage phagocytosis ability and amastigote proliferation of L. major or L. braziliensis by two different methods: fixation and staining of infected macrophages or recovery of promastigotes in culture.

Methods

Promastigote parasites were used to infect thioglycolate-elicited BALB/c mice peritoneal macrophages. Phagocytosis was evaluated at 3 h after infection and amastigote proliferation was evaluated directly or indirectly at 3, 6, and 9 days after infection.

Results

Phagocytosis of L. major and L. braziliensis by murine macrophages was respectively 54.38 ± 10.41% and 62.54 ± 19.01%, according to the fixation and staining method. The infection index (product of the percentage of infected cells X the number of parasites per cell) obtained by fixation and staining method showed proliferation of L. major inside macrophage from 108.42 ± 25.57 (3 h) to 510.09 ± 99.13 (9 days) and decrease of the number of L. braziliensis from 223.01 ± 58.46 (3 h) to 101.37 ± 20.06 (9 days). The parasites recovered/ mL in culture increased for L. major infected macrophage from 2,38 × 10⁶ ± 2,31 × 10⁶ (3 h) to 16,8 × 10⁶ ± 8,3 × 10⁶ (9 days) and decreased from 8.43 × 10⁶ ± 6.8 × 10⁶ (3 h) to 0.19 × 10⁶ ± 0.21 × 10⁶ (9 days) for L. braziliensis infected macrophage. The fixation and staining method allowed to observe that both parasite species proliferated inside of some macrophages, while other macrophages maintain the parasite number unaltered or even kill the parasite.

Conclusion

Both methods showed that L. major proliferates in vitro inside of murine macrophages while L. braziliensis are mostly eliminated by these cells. Only fixation and staining allowed to identify L. braziliensis susceptible macrophages in vitro.

Background

Intestinal parasitic infections (IPIs) and undernutrition in under-five children are a major public health concern in low and middle-income countries, contributing to childhood morbidity and disability.

Aim

This study aimed to investigate the effect of intestinal parasites on the anthropometric status of outpatients in under five children.

Methods

An institutional-based cross-sectional study was conducted at Assela referral hospital, Ethiopia from February 15 to March 30, 2024. Stool samples were collected from 227 children and examined using direct wet mount and formal ether concentration techniques. An Adjusted Odds Ratio analysis was done to test the association between intestinal parasitic infection and nutritional status (stunting, wasting and underweight).

Results

The prevalence of stunting, underweight, and wasting was 38(16.7%), 64(28.2%), and 59(26%), respectively. The total prevalence of parasitosis was 44(19.4%) of children infected with at least one type of intestinal parasite. The most common intestinal parasitic infections detected in the study were E. histolytica (8.4%), E. vermicularis (4.4%), and Giardia lamblia (3.5%). Residence (rural)(AOR = 2.46,CI 1.31–3.45,P = 0.02) fingernail cleanliness (not clean and also unclimbed AOR = 1.1,CI 1.1–2.3; P = 0.01 and climbed but not clean AOR = 1.22 CI 1.1–3.3;P = 0.01), parental education (unable to read and write AOR = 6.3 CI 1.3–19.1 P = 0.01 and Only able to read and write AOR = 2.91 CI 1.23–7.13;P = 0.02), deworming (lack of IPI treatment AOR = 3.1 CI 1.26–8.56 P = 0.01), water source (unprotected spring AOR = 1.21 CI 1.01–2.1 and unprotected river or stream AOR = 1.22 CI 1.04–4.3 P = 0.01) were more likely to be infected in intestinal parasites than the respective category. Undernutrition (stunting AOR = 4.1 CI 1.92–8.7; P = 0.02; underweight AOR = 8.5, CI 1.69–4.49; P = 0.01 and wasting AOR = 7.64, CI 4.1-16.64; P = 0.02) were significantly associated with intestinal parasitic infections at 5% significant level.

Conclusion

This study indicated that intestinal parasitic infections had significant effect on nutritional status of under five children in study area. To address the problem public health interventions activities were needed like deworming programs, health education, sanitation and nutritional improvement.

Background

Diseases transmitted by Aedes aegypti or Anopheles stephensi, such as Zika virus, dengue fever, and malaria, pose substantial risks to public health, particularly in tropical areas. Plant-derived compounds have emerged as promising alternatives due to their inherent safety and potential efficiency against mosquitoes. This study aimed to improve the efficacy of certain natural compounds, including α-pinene, citral, camphor, and thymol, by developing nanoliposomal formulations.

Methods

The ‎nanoliposomes containing α-pinene, citral, camphor, and thymol were prepared using the ethanol injection method and then characterized. Using WHO-recommended guidelines, their larvicidal efficacy was investigated against Aedes aegypti and Anopheles stephensi.

Results

The ‎nanoliposomes particle sizes were 105 ± 7, 86 ± 5, 149 ± 5, and 135 ± 8 nm, and zeta potentials ‎were − 25.1 ± 0.5, -17.2 ± 1.2, -16.4 ± 1.6, and − 21.3 ± 1.7 mV, respectively. In addition, the ATR-FTIR (Attenuated Total Reflectance-Fourier Transform InfraRed) analysis verified the successful loading of the compound. Nanoliposomal compounds exhibited superior performance compared to their non-formulated counterparts in larvicidal bioassays. The nanoliposomes containing thymol showed the highest efficacy, with a Lethal Concentration 50 (LC₅₀) of 20 µg/mL against Ae. aegypti. Nanoliposomes containing citral exhibited an LC₅₀ of 20 µg/mL against An. stephensi.

Conclusions

The results suggest that nanoliposomes have the potential to serve as an effective vehicle to improve the efficiency of plant-based larvicides. This could play a significant role in developing sustainable mosquito control strategies.

Background

Human toxocariasis is a helminthic zoonosis caused by infection of Toxocara canis or T. cati. Humans can be infected by through ingestion of embryonated eggs from contaminated water, food or soil. Diagnosis is challenging, immunodiagnosis tests are commonly implemented with major pitfalls in the cross-reactivity with other pathogens, particularly in endemic areas.

Methods

With the aim of identify species-specific genes encoding for highly expressed antigenic proteins, a list of parasites that may infect humans and that might present similar clinical symptoms to T. canis infections was built. Only organisms whose genomes were completely sequenced and the proteome predicted were included. First, orthologous proteins were detected and the subcellular localization of T. canis proteins was predicted. In order to identify differentially expressed genes encoding proteins in larvae L3, pair-wise comparisons among transcriptomes from body parts and genders were performed. Finally, all secreted proteins classified as species-specific of T. canis, whose genes were upregulated in larvae L3 were included in an antigenic prediction.

Results

Twenty-eight parasites were included in the analyses, proteins of T. canis were clustered in 11,399 groups, however, 279 were species-specific groups which represent 816 proteins. Three hundred and twenty-two proteins were predicted to be secreted and upregulated in larvae L3, however, after filtering these proteins by their orthology inference, only three proteins met all the features included in this study (species-specific, upregulated, secreted, and antigenic potential). To conclude, our strategy in the study is a rational approach for discovering antigenic proteins to be used in diagnosis.

Background

Leishmaniasis remains a significant global health concern, ranking among the top ten infectious diseases and causing substantial mortality and socioeconomic burden. Effective and accessible treatments are needed. This study investigated the potential of a hydroalcoholic extract from readily available urban green algae as an anti-leishmanial agent, focusing on its impact on key weight-related indicators of Leishmania major infection in BALB/c mice. To evaluate the in vivo anti-leishmanial activity of the hydroalcoholic extract from the common green algae genus Spirogyra against Leishmania major in BALB/c mice, specifically by assessing its effects on weight loss, lesion size, liver weight, and spleen weight—key indicators of disease progression.

Methods

Spirogyra algae were collected and identified in Yazd Province, Iran. A hydroalcoholic extract was prepared and administered via intraperitoneal injection into Leishmania major-infected BALB/c mice at doses of 3, 6, and 12 mg/kg/day, starting after lesion development. The control groups included untreated infected mice (negative control), healthy uninfected mice (control), and infected mice treated with Glucantime (positive control). We assessed treatment efficacy by monitoring weight loss, lesion diameter, liver weight, and spleen weight.

Results

Treatment with the highest concentration of Spirogyra extract (12 mg/kg/day) significantly mitigated weight loss in infected mice, demonstrating comparable efficacy to Glucantime. Both the 12 mg/kg/day algae extract and Glucantime significantly controlled lesion growth. Importantly, both treatments significantly reduced liver and spleen weight compared with the negative control group, indicating a reduction in organomegaly. Specifically, the negative control and 3 mg/kg extract groups exhibited the highest liver weights, whereas the negative control group showed significantly higher spleen weights than the other groups. The 12 mg/kg extract and Glucantime groups showed liver and spleen sizes comparable to the healthy control group, demonstrating effective control of organ size changes associated with leishmaniasis.

Conclusion

The hydroalcoholic extract of urban Spirogyra green algae, particularly at a dose of 12 mg/kg/day, exhibited significant in vivo anti-leishmanial activity in BALB/c mice. Evaluated through weight indicators such as reduced weight loss, controlled lesion growth, and normalized liver and spleen weights, the extract showed promise in mitigating the detrimental effects of Leishmania major infection and warrants further investigation as a potential source for novel anti-leishmanial therapeutics.

Objective

Bovine fascioliasis, a parasitic disease caused by Fasciola species, severely affects cattle health and agricultural productivity in tropical regions like Nigeria. It leads to economic losses through liver condemnations, decreased meat and milk production, and increased veterinary expenses. Despite its public health and economic significance, existing data on its prevalence and epidemiological patterns in Nigeria is limited.

Methods

This systematic review and meta-analysis compiled findings from 40 studies conducted between 1980 and 2024 to evaluate the prevalence and distribution of bovine fascioliasis in Nigeria.

Results

The analysis included 5,174,019 cattle and identified 120,678 infections, with a pooled prevalence of 29% (95% CI: 0.21, 0.38) using a random-effects model. A high level of heterogeneity was noted (I² = 100%, tau² = 0.0893). Subgroup analyses showed a higher prevalence in cross-sectional studies (33%, 95% CI: 0.25–0.42) compared to retrospective studies (18%, 95% CI: 0.04, 0.40). Diagnostic methods notably impacted prevalence estimates, with serological tests reporting 72%, versus 33% for microscopy and 22% for post-mortem examinations. Regional disparities were also evident, with the South-South zone exhibiting the highest prevalence in the country, underscoring the influence of environmental factors.

Conclusion

This study reveals the significant burden of bovine fascioliasis in Nigeria and highlights the need for region-specific, evidence-based control strategies. The findings also point to critical gaps in diagnostic standardization and surveillance, underscoring the necessity for improved diagnostic tools and integrated management practices to alleviate the effects of this parasitic disease.