Parasitologia, Volume 4, Issue 1 (March 2024) – 7 articles

The genus Erinaceus is commonly found in rescue centres across the European continent despite the reported decline in some countries. Parasite infections are frequently detected in rescued hedgehogs, leading to increased morbidity and mortality and consequently conditioning their recovery. Some of the most frequent parasites include respiratory nematodes, such as Crenosoma striatum and Capillaria spp., which may lead to important pneumonia. Moreover, some of these agents have zoonotic potential, such as Cryptosporidium spp., Sarcoptes spp., and several species of ticks and fleas, which may transmit different vector-borne pathogens. This review provides a brief guide on hedgehogs’ internal and external parasitology, as well as some suggestions for diagnosis and treatment that are relevant for wildlife veterinarians, biologists and other researchers. Full article

The presence of the Varroa destructor mite requires the use of acaricide treatments for honeybee colonies. Amitraz is one of the most common acaricide-active ingredients used by beekeepers. Certain Varroa mite populations have developed resistance to amitraz, thereby leading to a loss in the efficacy of amitraz-based treatments. Two products, Apivar and Supatraz, were applied in the same apiary in France to evaluate their efficacy. Both treatments are amitraz-based but have different galenics. Thanks to field data, a dynamic model was used to simulate the actions of Apivar and Supatraz on the mite population. We considered two parameters to compare the products as follows: the daily mortality rate and the treatment duration. In the field, the percentage of the efficacy of the two products was not significantly different, but Supatraz kills mites faster and decreases 90% of the mite infestation in 28.4 days compared with 50.9 days when using Apivar. Through modeling, we showed the daily impact of the two different products on mite population. Supatraz has a higher daily mortality rate during the first two weeks than Apivar. Supatraz requires a lower efficacy (% of varroa mites killed during all the treatment) to stabilize the varroa mite population due to its faster release of active ingredients than Apivar, thereby needing a shorter period to achieve the same result. Depending on the model, Supatraz conserves effective efficacy when used against moderately resistant mites (with mite mortality being 40–70% at the LC90) but not against highly resistant mites (with mite mortality being <40% at the LC90). These results show that the comparison of the efficacy of the two products with different characteristics (duration of treatment and daily mortality rate) should be analyzed with caution. Full article

Chamois are mountain ungulates (Artiodactyla: Caprinae) which inhabit several medium- and high-altitude mountain ranges from southern Europe to the Near East. The first findings of Sarcocystis cysts in the musculature of chamois were reported in the 1970s. However, only limited work on the epidemiology of sarcocystosis and the identification of the species of Sarcocystis in chamois has been carried out in the past. The present study aimed to provide, for the first time, data on the prevalence and intensity of Sarcocystis spp. Infection in native Alpine chamois using a histology examination of heart and/or diaphragm tissue samples collected from 216 chamois (40 kids [<1 year] and 176 chamois ranging up to 18 years of age). Sarcocysts were detected in either the heart or diaphragm of 167/216 chamois (77.3%), with 131 of 183 heart samples and 127 of 215 diaphragm samples testing sarcocyst-positive. Of the 181 chamois with both heart and diaphragm samples available (34 kids and 147 older animals), sarcocysts were detected in the heart and/or diaphragm of 142 animals, translating to an overall 78.5% prevalence of Sarcocystis spp. infection (95%CI 72.5–84.4%). Sarcocysts were more frequently recorded in the heart vs. diaphragm (72.4% vs. 56.4%; p = 0.0021), and diaphragm positivity was associated with heart positivity (p = 0.0001). The sarcocyst prevalence (heart and/or diaphragm) was significantly (p < 0.001) lower in the kids than in the older chamois (27.1% vs. 88.6%, respectively); however, it did not differ between the sexes, regardless of the chamois’ age (p > 0.3). The intensity of infection was generally low (<10 sarcocysts per cm² muscle cut) in both heart-positive and diaphragm-positive animals (94.7% and 93.7%, respectively). The heart tissue yielded higher sarcocyst counts than the diaphragm tissue (p < 0.001). Both the heart and diaphragm sarcocyst counts were significantly (p < 0.001) lower in the kids than in the older chamois. Sarcocystis spp. infection was demonstrated to be prevalent in chamois in Germany, but its intensity is apparently low. Further studies are desired to identify the species of Sarcocystis parasitizing the chamois using both phenotypic and molecular characteristics. Full article

For years, there has been an increasing interest in natural alternatives to the conventional coccidiostats applied as feed additives, which have been used for decades to prevent coccidiosis in poultry and fattening rabbits. This study aimed to compare the possible anticoccidial effects of oregano oil to the established substance diclazuril in growing rabbits. The control group (CG) received a non-supplemented basal compound feed, to which either diclazuril (1 mg/kg; DG) or oregano oil (75 mg/kg; OG) was added. In each of the three trials, subgroups of 50 rabbits each were assigned to one of the three experimental groups (CG, DG and OG). Natural Eimeria infection was monitored weekly by fecal oocyst counts and Eimeria species identification following sporulation. Additionally, the performance parameters were determined at the middle and the end of the trials, and the deceased rabbits were subjected to necropsy. Neither oocyst excretion nor the performance parameters differed significantly between the three experimental groups. Eimeria media, Eimeria magna, Eimeria perforans and Eimeria exigua were identified as the occurring species. The highest animal losses (16.0%) occurred in the OG, while the losses were 12.7% in the DG and 12.0% in the CG. However, these differences were not statistically significant. Overall, neither diclazuril nor oregano oil was superior to the non-supplemented feed. This underlines the importance of diagnostics, as this study’s results indicate that in the absence of the highly pathogenic Eimeria species, economic rabbit rearing and fattening is achievable without the use of coccidiostats. Full article

The success of any tsetse control program depends on the knowledge of their behaviour. This study assessed the host choice and feeding behaviours of Glossina morsitans siblings whose parents were bloodfed on rabbits, guinea pigs, rodents, and squirrels. Each individual host was placed in a screen cage, which allowed flies to enter through openings on each side. The groups of flies (20 per replicate), which were colour-marked differently based on their parents’ blood meal hosts, were released from the centre of large semi-field cage. The released flies were aspirated after 24 h and then sorted based on their location, feeding status, and parents’ blood meal. A total of 213 flies (72.95% of those recovered) were attracted to the hosts. The numbers of flies attracted to different hosts varied significantly (χ²₄ = 33.685, p = 0.0001): rodents (n = 80, p = 0.006), rabbits (n = 59, p = 0.331), guinea pigs (n = 49, p = 0.057), and squirrels (n = 25, p = 0.005). The numbers of flies attracted to their parent’s blood meal source varied significantly (χ²₁₂ = 56.476, p < 0.001): rabbits (n = 35, 59.32%, p < 0.001), rodents (n = 25, 31.25%, p = 0.043), and guinea pigs (n = 19, 38.78%, p = 0.45). But only 39 flies (18.31% of the total attracted) bloodfed on the hosts, including guinea pigs (n = 10, 25.64%), rodents (n = 23, 58.97%), rabbits (n = 6, 15.38%), and squirrels (n = 0, 0.0%). There was significant variation in the number of flies that fed successively across hosts (χ²₄ = 49.478, p < 0.001). The findings from this study confirm the presence of differential attractiveness of the hosts to flies and the so-called “Hopkins host selection principle” or “pre-imaginal conditioning”. Therefore, the study attracts the need for detailed investigation on the influence of blood meal sources on tsetse fly siblings’ behaviours across filial generations using small mammals or other large mammal species. Full article

Acanthamoeba castellanii is a free-living amoeba capable of causing keratitis in humans, with most cases related to contact lens wearers and surgical procedures. In addition, A. castellanii may cause pneumonia, granulomatous encephalitis, and skin lesions in immunocompromised individuals. Considering the lack of adequate treatment for acanthamoebiasis, the aim of this review is to assess relevant original articles that covered the current arsenal of drugs and models of organisms used in the field of experimental A. castellanii infection that have been published within the last 5 years (2018–2023) in journals indexed by the following databases: Electronic Library Online (SciELO), PubMed, Medical Literature Analysis and Retrieval System Online (Medline), Latin American and Caribbean Literature in Health Sciences (Lilacs), Google Academic, and Capes Periodical Portal. Thirty articles were selected, and the main findings showed that the available therapeutics for acanthamoebiasis are still limited and nonspecific, and no innovations have occurred in the last few years. In terms of novel chemotherapeutic advances, the last findings have focused on the activity of natural products (plant-based extracts), nanoemulsions, coated particles, and photodynamic association against A. castellanii, without advancing from the bench to bedside perspective. The choice of a non-representative model system for acanthamoebiasis, as well as the limitations of studies in vivo, impairs the advancement of toxicity analyses. Efforts should be made to expand the model systems used, standardize tests for evaluating anti-A. castellanii drug candidates, and increase and support research groups focusing on the biology of A. castellanii and the pharmacology of acanthamoebiasis. Full article

We assessed the prevalence of soil-associated parasites and non-pathogenic nematodes in eight public areas of Porto Alegre (Rio Grande do Sul state, southern Brazil), the most populous city in Rio Grande do Sul. Soil samplings were carried out during the winter of 2022 and summer of 2023: A total of 80 samples were collected in winter and 80 in summer (ten samples from each sampling site per season), totaling 160 soil samples. The frequency of microscopic non-pathogenic nematode larvae was significantly higher (p = 0.048) in winter (93.75%) than in summer (82.50%). Considering the pooled data from winter and summer (n = 160) for human pathogenic parasites, the following frequencies were observed (using microscopy analysis): hookworm (filariform) larvae (1.25%), hookworm (rhabditiform) larvae (11.25%), Strongyloides spp. (filariform) larvae (0.63%), Strongyloides spp. (rhabditiform) larvae (2.5%), hookworm eggs (10.63%), Ascaris spp. eggs (10.00%), and Trichuris spp. eggs (1.25%). Hookworm (rhabditiform) larvae were the most frequent parasitic structures (15.00%) in winter, and A. lumbricoides eggs were the most frequent parasitic structures (8.75%) in summer. No statistically significant difference was observed in the frequency of pathogenic parasites between the seasons (p > 0.05). Toxoplasma gondii DNA was assessed, but all soil samples tested negative in molecular analysis. Our results indicate that soil from many regions of Porto Alegre shows a high prevalence of soil-transmitted helminths, indicating the need for improvements in social conditions and environmental sanitation in the city. Our study also suggests that climate change may affect soil biodiversity, potentially harming non-pathogenic nematodes and favoring human pathogenic parasites. Full article