Parasitologia, Volume 1, Issue 3 (September 2021) – 8 articles

This review describes the advances acquired and proven in the use of helminthophagous fungi in the control of gastrointestinal helminth parasites in domestic animals. Old and well-known premises about parasitic epidemiology and the factors that can interfere with the best performance of biological control are mentioned. Some of the most promising fungi are Duddingtonia flagrans from the predatory fungi group and Pochonia chamydosporia and Mucor circinelloides from the ovicidal fungi group. These fungi produce resistance spores called chlamidospores. Bioverm^® and BioWorma^®, based on the fungus D. flagrans, are available as commercial. Biotechnological products such as nanoparticles and obtaining primary and secondary metabolites have already been obtained from these fungi. Because they have different mechanisms of action, ovicidal and predatory fungi, when used together, can present a complementary and synergistic action in the biological control of helminths. Therefore, future research in the search for new formulations, the association of fungi from different groups, extraction of new molecules, and nanoparticles of these fungi in the control of helminths in various domestic animals are desired. Full article

Echinococcus multilocularis is a tapeworm causing severe zoonotic disease in temperate Europe. Between 2018 and 2020, 68 golden jackals and 94 red foxes were investigated to determine the prevalence of E. multilocularis infection and its driving factors. The overall prevalence (golden jackal: 41.2%; red fox: 12.5%) significantly differed, whereas the mean intensities did not. The spatial scan statistics revealed three significant clusters of E. multilocularis infection. The binary logistic and ordinal regression results revealed that the golden jackal is more likely to become infected than the red fox, and the probability of infection level was also higher in jackals. Our findings highlight the golden jackal’s role, which could be as important as the red fox in the spread of this severe zoonotic agent. This micro-epidemiological approach can advance the knowledge on local drivers which facilitate the spread of E. multilocularis and could cause a relevant public health problem on the continent. Full article

Parasites remain a significant threat to horses’ health and welfare. The present paper reviews and discusses interactions between parasitic infections and reproductive efficiency in horses. The manuscript describes the interactions in a structured way, presenting the infecting parasites and the respective effects in the reproductive activity of horses. The following stages of the reproductive cycle are covered: ovarian activity and relevant body condition, breeding management (including effects in mares and stallions), pregnancy and neonatal period. A separate section covers the topic of transmission of pathogens to horses through parasites. Finally, parasite control strategies in relation to reproductive activity (strategies for breeding mares and foals) are discussed. Understanding the causality of impaired reproductive performance is essential in terms of maintaining productivity and efficient stud breeding strategies. Further collaboration of parasitologists, stud managers and veterinarians is necessary in order to implement novel control strategies with a greater emphasis on the emerging challenges. Full article

Diversity and phenology of host-seeking ticks were studied in the Flint Hills region of the USA, which is a prominent region for raising beef cattle. Between a two-year period from 2015–2017, ticks were collected using the dragging method from 9 distant locations, 6 of which were studied seasonally and 3 continuously throughout the study period. Of the 10,055 ticks collected, 76.5% were the Lonestar tick (Amblyomma americanum), 14% were American dog tick (Dermacentor variabilis), and 9.1% were Gulf Coast tick (A. maculatum). The blacklegged tick, Ixodes scapularis were also found, albeit in low numbers. The host-seeking activity of all three predominant tick species peaked once during the late spring, summer months in the region. The phenology of all ticks was positively associated with accumulated temperature and photoperiod. Additionally, the Normalized Vegetation Difference Index (NDVI) was associated with A. americanum, and saturation deficit and relative humidity were negatively associated with D. variabilis and A. maculatum tick phenology, respectively. This finding is useful to predict the times during a year in which cattle are at higher risk for exposure to these ticks and associated pathogens. Full article

Dirofilaria immitis and Dirofilaria repens are mosquito-borne pathogens responsible for dirofilariasis in humans and animals. Their transmission and spread depend on the activity of vectors and the frequency of hosts in a given area. Here, we investigated the efficacy of a monthly multimodal prophylactic (MMP) strategy against canine dirofilariasis on Corsica Island (France). The study was conducted as evidence of an efficacy trial in which eighty dogs were divided into two groups: (i) one test group consisted of 25 dogs under the MMP [per-os administration of 1.5 tablets of milbemycin-oxime-praziquantel (Milbactor^®) and a topical line-on application of a 3.6 mL solution of dinotefuran-permethrin-pyriproxyfen (Vectra^® 3D)] and (ii) a control group under different real-life prophylactic treatments (RLP) based on the use of ectoparasiticides (different formulations: deltamethrin, fluralaner, fipronil) and/or macrocyclic lactone-based products (milbemycin-oxime/praziquantel, milbemycin-oxime, moxidectin) during the period from June to October 2017. All animals were followed up for one year, with blood collected at day 0, with follow-up at 6 and 12 months. Samples were tested for Dirofilaria spp. by species-specific qPCR. At the end of the study, no new case of Dirofilaria spp. infection was detected in the test group. However, the cumulative incidence of Dirofilaria spp. infection was 16.4% (n = 9; p = 0.027) in the control group. The data illustrate that, in contrast to RLP treatment, which failed to protect at least 16.4% of dogs, the MMP based on the simultaneous administration of milbemycin oxime-praziquantel and dinotefuran-permethrin-pyriproxyfen efficiently protects dogs in a high-risk area from Dirofilaria spp. infection. Full article

Swimming pool water treatment by chemicals is an essential step to avoid microbial proliferation and infections namely caused by free living amoeba such as, for example, primary amebic meningoencephalitis and Acanthamoeba keratitis. In the present study, a commercial reactive, CLORICAN, based on chlorine dioxide, was evaluated against Acanthamoeba spp. and Naegleria fowleri. We observed that CLORICAN could eliminate in a short period of incubation time both amoebae. Furthermore, Naegleria fowleri’s trophozoites were more sensitive than those of Acanthamoeba spp. By means of inverted microscopy, the chlorine dioxide was found to greatly affect morphology shape by increasing the cell size shrinkage. Full article

Soil-transmitted helminths (STH) including the hookworms Necator americanus and Ancylostoma spp., Ascaris lumbricoides, and Trichuris trichiura affect over 1.5 billion people worldwide and are estimated to have caused 1.9 million disability-adjusted life years (DALYs). With the concerted effort in expanding and improving targeted mass drug administration (MDA) programs over the past decade, along with decreasing prevalence, infections in several endemic areas tend to be of low intensity. Conventional microscopy-based methods recommended for the detection of STH in parasitological surveys have been shown to be less sensitive in these low-intensity settings. As communities progress towards STH elimination through MDA and improved sanitation, there is a pressing need for highly sensitive techniques that detect the true prevalence of STH to evaluate the effectiveness of ongoing programs and interventions. Molecular methods that involve analysis of DNA rather than the morphology of the organism are highly sensitive and specific, allowing for both quantitation and species discrimination. The following review discusses different sample collection strategies, pre-processing steps, DNA extraction platforms, and nucleic acid detection methods available for diagnosis and surveillance of STH. We have contrasted the utility of these molecular tools against conventional microscopy-based methods currently used in most endemic settings. While the detection methods are primarily qPCR based, several newer technologies have also become available along with automation and increased throughput, making these molecular tools increasingly cost-effective and potentially amenable for use in low-resource settings. Full article

The control of soil-transmitted helminthiasis (STH) in Cameroon is focused on large-scale deworming through annual mass drug administration (MDA) of albendazole or mebendazole to at-risk groups, principally pre-school and school-age children. After a decade of intervention, prevalence and intensity of infection have been significantly lowered, encouraging the paradigm shift from control to elimination. However, STH eggs are extremely resistant to environmental stressors and may survive for years in soils. It therefore appeared important to assess whether the risk of transmission was still prevailing, especially in a context where transmission of soil-transmitted helminths in the human population had almost been interrupted. A retrospective and a prospective cross-sectional surveys were conducted in five Health Areas of the Mifi Health District (West Region, Cameroon) to: (i) assess the trends in infestation rates over three-years (2018–2020) using health facility registers, and (ii) investigate, in 2020, the contamination rates of the environment by dissemination stages of soil-transmitted helminths using the sucrose centrifugal flotation method. The overall soil-transmitted helminth infestation rate was 4.9% (95% CI: 4.3–5.6), significantly lower than the overall soil contamination rate (12.0%; 95% CI: 8.2–17.2). These results are supportive of the low endemicity level of STHs in the Mifi Health District, but environmental pollution by dissemination stages of the parasites outlines that the risk of transmission is still persistent. It therefore appears compulsory to account for the environment when considering policy/recommendations for transmission interruption and stopping MDA, as it is in the case with vector-borne diseases. Full article