Acta Parasitologica最新文献

Malignant tumors are prevalent with high mortality rates in humans, dogs, and cats. Some microorganisms have been shown to inhibit cancer progression. The objective of this study is to evaluate the inhibitory effects of Neospora caninum, a livestock parasite, on three different tumor models in C57BL/6 mice, including Lewis subcutaneous tumors, Lewis and B16F10 melanoma lung metastasis. The results showed that a sufficient amount of N. caninum tachyzoites can significantly inhibit the development of subcutaneous tumors and lung metastasis (P < 0.001), and induce more than 50% tumor cell death in Lewis subcutaneous tumors. N. caninum treatment can significantly increases the infiltration of macrophages, NK cells, and CD8⁺ T cells (P < 0.0001) in Lewis subcutaneous tumors detected by immunohistochemistry, and the percentage of these immunocytes in the spleen (P < 0.05) of mice bearing B16F10 melanoma metastasis detected by flow cytometry. And with these changes, the mRNA expression levels of IL-12, IFN-γ, IL-2, IL-10, TNF-α and PD-L1 in tumor microenvironment and IL-12, IFN-γ, IL-2 in spleen were also significantly increased (P < 0.05). Altogether, our results indicate that a sufficient amount N. caninum tachyzoites not only inhibits the growth of Lewis subcutaneous tumors, but inhibits the development of Lewis and B16F10 melanomas lung metastatic in mice by activating potent immune responses. N. caninum and its anti-tumor properties may be an effective anti-tumor tool.

Purpose

Acanthamoeba spp. can colonize various freshwater habitats. They are the causative agents of granulomatous amoebic encephalitis and can harbor many microorganisms. We studied the presence of Acanthamoeba spp. in the water system of a hemodialysis unit and assessed the potential for transmission to hemodialysis patients.

Methods

Water samples collected from pretreatment and posttreatment water of the treatment station and from input and output water of the dialysis machines were cultured on non-nutrient agar supplemented with Escherichia coli. Blood samples from dialysis patients in the unit and from a control group in the same hospital were tested for anti-Acanthamoeba IgG antibodies.

Results

Acanthamoeba spp. were found in posttreatment water. They were more commonly found in the input water samples (79.2%), than in the output water samples (16.7%) (p = 0.001). Anti-Acanthamoeba IgG antibodies were present in 32.9% of patients and were absent in the control group (p = 0.002). The duration of hemodialysis was significantly longer in seropositive patients than in seronegative patients (p = 0.008).

Conclusion

The study highlights the presence of Acanthamoeba spp. in the dialysis system. The relatively high prevalence of anti-Acanthamoeba IgG antibodies and the link between dialysis duration and seropositivity emphasize the importance of rigorous water monitoring.

Purpose

Aedes albopictus, known as the Asian tiger mosquito, is an extensively studied mosquito species recognized for its rapid global expansion and its capacity to transmit a range of viruses such as dengue, chikungunya, Zika, and yellow fever viruses. In 2010, Ae. albopictus was observed for the first time in Tizi-Ouzou, Algeria, and since then has colonized all the northern part of the country until the semi-arid areas. The present study was devoted to the molecular characterization of Ae. albopictus in Algeria.

Methods

A total of 20 selected mosquitos,originated from collected eggs in five different districts of northern Algeria weretested by PCR amplification and sequencing of the Cytochrome c oxidase subunit 1 a (COIa).

Results

Pairwise alignment of the obtained sequences with representative Ae. albopictus available COIasequences of the world exhibit 117 different haplotypes. The Algerian sequences are grouped in 1 haplotype shared with Morroco, Madagascar and Mauritius in Africa and 3 other continents (Asia, Europe and America). Asia expresses the highest genetic and nucleotidic diversity (Hd = 0.828;π = 0.0144). In China two new species not described in the literature and confused with Ae. albopictus are detected.

Conclusion

These results could be used as preliminary data to study and develop targeted control strategies to prevent this vector from spreading in Algeria.

Purpose

Bovine anaplasmosis is a major tick-borne disease in ruminants, resulting in significant economic loss for the dairy sector. This study aimed to evaluate the seroprevalence of Anaplasma marginale (A. marginale) in buffaloes in three governorates in Nile Delta of Egypt.

Method

A total of 400 serum samples from water buffaloes were examined using commercial cELISA kit.

Results

The overall seroprevalence of A. marginale was 12.5% and Kafr ElSheikh governorate has the highest seroprevalence rate (15.28%). The seroprevalence was higher in females (13.33%) than males with non-significant difference. Moreover, adult animals older than 8 years exhibited a significant risk for A. marginale seropositivity (22.92%), particularly during the summer (22.52%) and autumn (13.73%). Significant differences (P < 0.05) in seroprevalence rates were observed between tick-infested animals (14.96%) and those not treated with acaricides (17.7%), highlighting the influence of tick infestation and lack of acaricidal intervention on infection rates.

Conclusion

The present study revealed the existence of antibodies against A. marginale in water buffaloes reared in Nile Delta of Egypt. Thus, the proper policies and control program should be adopted to reduce spreading of infection.

Purpose

Malaria remains a major global health challenge, particularly in sub-Saharan Africa and low- and middle-income countries (LMICs), contributing substantially to mortality and morbidity rates. In resource-limited settings, access to specialized diagnostic tests is often restricted, making basic blood analysis a valuable diagnostic tool. This study investigated the correlation between malaria infection and full blood count values in a rural region of Ghana during the 2022 rainy season, aiming to highlight diagnostic insights available from routine blood analyses.

Methods

A retrospective case-control analysis was conducted on 544 confirmed malaria cases, comparing their blood values with those of matched malaria-negative controls.

Results

Parasitaemia levels peaked during the rainy season, with July showing the highest values. Malaria-positive patients exhibited lower levels of haemoglobin, white blood cells, lymphocytes, and platelets, but higher neutrophil counts compared to controls. Middle-aged women had significantly lower haemoglobin levels than men, and younger individuals showed higher parasitaemia levels. A negative correlation was found between Plasmodium density and haemoglobin and platelet counts, while positive correlations were observed with white blood cell and neutrophil counts.

Conclusion

This study highlights the significant burden of malaria in rural Ghana during the rainy season and underscores the impact of infection on blood values. Routine full blood count analysis provides a practical and accessible diagnostic tool in resource-limited settings. The findings emphasise the importance of targeted interventions for high-risk groups, particularly children and women, to improve patient management and reduce malaria-related morbidity.

Graphical Abstract

Purpose

This work described a new species of Ceratomyxa, based on morphological and phylogenetic analyzes of myxospores collected from the gallbladder of the fish Astyanax mexicanus.

Methods

Sixty-two specimens were captured, between December 2022 and February 2024, in the Flexal River, in the community of Tessalônica, state of Amapá. The specimens were transported alive to the Laboratory of Morphophysiology and Animal Health, at the State University of Amapá, where the studies were carried out.

Results

Eleven specimes of A. mexicanus was parasitized with Ceratomyxa tessaloniensis n. sp. Morphological and morphometric analyses revealed strongly arched spores that measured 3.13 ± 0.5 μm in length and 12.18 ± 1.9 μm in thickness with a posterior angle of 74º ± 10.6º and two polar capsules measuring 1.74 ± 0.1 μm long and 1.5 ± 0.16 μm wide. The partial sequence of the 18 S gene from spores of Ceratomyxa tessaloniensis n. sp., comprised 932 base pairs.

Conclusion

Phylogenetic analysis grouped Ceratomyxa tessaloniensis n. sp., with strong nodal support for the exclusive clade of freshwater species, being a new species described for the State of Amapá, the first described in A. mexicanus and the first species with the presence of non-wormlike plasmodia in South America.

Introduction

Toxocarosis in human beings is currently diagnosed by serological assay based on the detection of antibodies against Toxocara antigens. Toxocara canis larvae do not reach the adult stage in paratenic hosts like humans and mice. Therefore experimental infection in mice, which mimics the biology of human infection, might be relevant to get a better understanding of human toxocarosis.

Methods

Two recombinant antigens viz. rTc-CTL-1 and rTES-120 were developed by expression of respective genes in Escherichia coli. The Balb/c mice were divided into 3 groups; Group I and group II (n = 8 mice each) were infected orally with 100 and 1000 T. canis embryonated eggs, respectively and Group III, mice served as uninfected control mice. The serum samples were obtained from all mice at 0, 7, 14, 28, 45, 60, 90, 120 and 150 days post infection (dpi) were tested by indirect ELISA for detecting seroreactivity to Toxocara and at 28 dpi sera of mice was used for confirming seropositivity of toxocarosis in experimentally infected mice.

Results

The rTc-CTL-1 antigen based ELISA showed the antibody response in both the infected groups were increased from 7 dpi, reached maximum at 28 dpi, then gradually declined but it was maintained up to 150 dpi where as the rTES-120 antigen based ELISA detected antibody only at 28 dpi with a maximum at 60 dpi, then moderately declined but it was observed up to 150 dpi. The antibody response of group II mice were significantly higher than the group I mice throughout the observation period when compared to control group (P < 0.01). Statistical analysis showed a highly significant difference in the antibody response between the group I and group II mice from 14 to 150 dpi with rTc-CTL-1 ELISA and from 28 to 150 dpi with rTES-120 based ELISA (P < 0.01). The seropositivity in mice sera samples at 28 dpi using rTc-CTL-1 based ELISA revealed 87.5% in group I and 100% in group II mice were positive. The rTES-120 ELISA revealed 12.5% in group I and 25% in group II mice were positive. Statistically highly significant difference in the seropositivity between the recombinant antigens (P < 0.01) was observed, but, there was no significant difference between the infected group of mice.

Conclusion

It was concluded that rTc-CTL-1 antigen based ELISA detect antibody in early infections compared to rTES-120 ELISA and also the antibody response was directly proportional to the dosage of infective eggs. The diagnostic efficacy of rTc-CTL-1 antigen based ELISA was better when compared to rTES-120 antigen based ELISA.

Purpose

This study aimed to assess the anticoccidial effects of betaine and a vaccine compared to monensin sodium in experimentally induced coccidiosis in broiler chickens.

Methods

600 day-old broiler chickens (Ross 308) were randomly assigned to five groups, each with four replicates of 30 birds. While the control group received a basal diet, two experimental groups received basal diet supplemented with either 100 mg/kg monensin sodium or 2.0 g/kg betaine. The remaining experimental groups received a commercial coccidiosis vaccine alone or in combination with betaine. All chickens were challenged with sporulated field-mixed Eimeria species at 20 days of age.

Results

Throughout the study, vaccinated birds showed superior performance in terms of body weight gain (BWG) and feed conversion ratio (FCR) compared to other anticoccidial treatments (P < 0.05), followed by betaine, vaccine + betaine, and monensin treatments in descending order. While all anticoccidial regimens significantly reduced fecal oocyst output only at the beginning of the observation period, this effect diminished thereafter (P < 0.05). Supplementation with monensin and vaccination against coccidiosis significantly decreased small intestine weight compared to untreated controls (P < 0.01), with a numerical decrease observed in chicks fed betaine-supplemented diets and treated with the combination of betaine and vaccine.

Conclusion

Notably, there has been no prior study comparing betaine with monensin sodium and a coccidiosis vaccine. These findings suggest that dietary betaine supplementation and a commercial coccidiosis vaccine containing mixed Eimeria spp. may offer benefits in controlling coccidiosis, presenting viable, cost-effective, sustainable, and safe alternatives to conventional ionophore anticoccidials, with added benefits of no residue and reduced resistance hazards for both animal and human consumption.

Purpose

Bats constitute 20% of all mammal species, playing a vital role in ecosystem health as pollinators, seed dispersers, and regulators of insect populations. However, these animals can also be reservoirs for infectious agents, including viruses, bacteria, and enteroparasites such as Cryptosporidium spp., Giardia duodenalis, and Balantioides coli, raising questions about their role in the epidemiology of these agents. Our study analyses bat faecal samples from Portugal with the aim of assessing the prevalence, distribution and diversity of enteroparasitic protozoa.

Methods

We conducted a retrospective study that included 380 bat faecal samples collected between 2014 and 2018 in northern and central Portugal.

Results

In our study, a Cryptosporidium spp. prevalence of 3.2% was identified, with genetic diversity observed and strains grouped with known bat genotypes. Giardia duodenalis was detected in 0.5% of the samples, exhibiting distinct genetic characteristics that may suggest a potential new assembly group encompassing bats and rodents. Finally, B. coli was detected in 0.26% of samples, representing the first observation of this ciliate in bats, with the identified genetic variant belonging to genotype B.

Conclusion

Our results provide valuable molecular epidemiological insights that underscore the importance of bats in the epidemiology of these enteroparasites. Furthermore, this is the first report of Cryptosporidium spp. and G. duodenalis in bat faeces samples from Portugal, and the first study worldwide to show that bats can shed B. coli in their faeces.

Background

Ligophorus Euzet and Suriano, 1977 is a specious genus of ancyrocephalid monogeneans parasitizing mullets around the world, with most species distributed in the western Pacific and the Mediterranean Sea. Only nine out of the 62 species in the genus have been reported from the Americas, and from them, only two have been sequenced.

Methods

We analyzed two species of Mugil (L.) from Northern Yucatán Peninsula. Specimens of Ligophorus were sampled from the gills of their hosts. The morphology of the specimens was examined. In addition, 28S and ITS rDNA sequences were obtained and compared with previous sequences downloaded from GenBank.

Results

We discovered two species of Ligophorus using morphological and molecular characters, L. mediterraneus, parasitizing the stripped mullet Mugil cephalus off the coast of Celestún, and L. yucatanensis, parasitizing the silver mullet M. curema in four coastal lagoons. Sequence data of the latter species are reported for the first time.

Conclusion

Our findings showed that two species of Ligophorus occur in mugilids of the Yucatán Peninsula. One represents a widely distributed marine species with records in the Mediterranean Sea and the Yucatán Peninsula, whereas the second one, L. yucatanensis, represents an endemic species restricted to coastal lagoons of the Yucatán Peninsula.