Parasitologia, Volume 1, Issue 4 (December 2021) – 9 articles

The construction of dams along the Senegal River resulted in an increase in irrigated land areas and changes in the epidemiology and transmission of water-related diseases. The objective of this study was to update epidemiological data on malaria in Rosso, one of the major Mauritanian cities along the Senegal River. Febrile patients (n = 318) were screened for malaria using a rapid diagnostic test (RDT) for malaria and microscopic examination of blood smears. Diagnosis was later confirmed by polymerase chain reaction (PCR). The mean age of 318 febrile patients was 25.1 (range 1–80 years). Only 7 (2.2%) and 2 (0.6%) had a positive RDT and thick smear, respectively. PCR confirmed the diagnosis in two Plasmodium vivax-infected patients. Most participants (198/318, 62.3%) had no recent travel history outside Rosso. The majority of the febrile patients (90%, 284/311) owned at least one insecticide-treated net (ITN). The frequency of the use of ITNs was not significantly associated with season (rainy vs. dry seasons; p = 0.9) or with the number of ITNs per household (r_s = 0.07; n = 285; p = 0.19). Of 285 individuals with ITNs, only two (0.7%) with no travel history were PCR-positive for malaria. Despite the presence of mosquito breeding sites related to rice irrigation, malaria transmission in Rosso remained very low, possibly due to the high coverage and frequent use of bed nets. Regular entomological surveillance for possible changes in the prevalence of Anopheles mosquito species and their behavioural aspects should be implemented. Full article

Rhipicephalus sanguineus s.l. and Ctenocephalides felis are considered the most prevalent ectoparasites of dogs in the Philippines. Vector-borne pathogens (VBPs) in these ectoparasites pose health risks to humans and animals. This study aimed to confirm the morphological and molecular identity of tick and flea species parasitising dogs in Metro Manila (Philippines) and molecularly investigate the possible presence of Bartonella spp., Rickettsia spp., Ehrlichia canis, and Anaplasma platys DNA. Ticks (n = 58) and fleas (n = 52) on dogs from three veterinary clinics in Metro Manila were collected and identified morphologically and molecularly via amplification and sequencing of cytochrome c oxidase I (cox1). Aliquots of ectoparasite DNA underwent real-time polymerase chain reaction (qPCR) screening for VBPs. All ticks were R. linnaei (formerly R. sanguineus s.l. “tropical lineage”), while all fleas were C. felis from clade 6 of the tropical II cluster/“Cairns” clade known from Australia. DNA of B. clarridgeiae was detected in 10% of fleas. DNA of R. felis was detected in 10% of fleas and in 3.8% of ticks. DNA of E. canis and A. platys was not detected. This study confirmed the presence of ticks and fleas as frequent ectoparasites on dogs and VBP presence emphasises the importance of preventative actions for animal health and welfare. Full article

Echinococcus granulosus is endemic in the Magallanes region and other areas of Chile. After a successful control programme implemented between 1979 and 2004, dogs’ prevalence decreased from 70% to 0.5%. Since the end of the programme, no prevalence study of canine echinococcosis has been performed in this region. Dog faecal samples were collected from epidemiological units for DNA isolation and polymerase chain reaction (PCR) to detect E. granulosus. In addition, dog owners were required to answer a questionnaire for a risk factor analysis. We collected 1069 environmental dog faecal samples from 267 urban, 241 periurban, and 61 rural epidemiological units. E. granulosus was found in 11/61 (18%) and 1/241 (0.4%) epidemiological units from rural and periurban areas, respectively. The Ultima Esperanza province showed the highest prevalence with eight out of 16 units with faeces positive to E. granulosus showing a main spatial cluster of canine echinococcosis. None of the risk factors investigated showed a statistical significance with positive units. This study shows the active transmission of the parasite in the Magallanes region, especially in the Ultima Esperanza province, with a possible re-emergence of the parasite. Further studies focusing on the incidence in humans are required together with the reestablishment of the compulsory deworming of dogs. Full article

Visceral leishmaniasis (VL) is one of the most severe clinical manifestations of leishmaniasis as it leads to death in 90% of untreated cases. The liver, spleen and bone marrows are the organs most affected; however, Leishmania parasites are able to reach the intestines where the gut-associated lymphoid tissue (GALT) is located. Under physiological conditions, the gastrointestinal tract and GALT interact with the enteric nervous system (SNE); however, there are no studies exploring the modulatory role of Leishmania (Leishmania) infantum in the intestines. Thus, this work aimed to investigate the parasitism, stratigraphy, and morphological changes in the myenteric plexus of golden hamsters infected with L. (L.) infantum. The animals were infected intraperitoneally, and the parasite load was evaluated in the spleen, the liver, and the jejunum. The stratigraphic evaluation and the quantitative and morphometric analyses of NADH-dp and NADPH-dp myenteric neurons were studied at 30-, 60-, and 90-days post-infection (DPI). Parasites in the spleen, the liver, and the jejunum increased during the progression of the infection. Stratigraphy studies showed a significant hypertrophy of the villi and the crypts associated with the increased intraepithelial lymphocytes that were observed in the jejunum of the infected animals. In addition, mucosal atrophy associated with a reduction in AB+ and PAS+ goblet cells was observed at 60 DPI and 90 DPI. These morphological changes were associated with an atrophy of the cell profile from NADPH-dp myenteric neurons. Furthermore, a significant decrease in the densities of this neuron population was observed in the chronic phase of the infection. This study suggests that L. (L.) infantum parasites are able to alter the morphology and innervation of the jejunum in golden hamsters. Full article

5-aminolevulenic acid (ALA), an endogenous, non-proteinogenic, naturally occurring amino acid found in diverse organisms, is a precursor of heme biosynthesis. For apicomplexan protozoan parasites, an ALA and sodium ferrous citrate (SFC) combination was previously evaluated and suggested as a potential drug candidate for Plasmodium falciparum malaria. This study aimed to evaluate the potential of this combination against bovine babesiosis. ALA administration at 100 and 500 µM coupled with 10 µM SFC in culture medium significantly inhibited intraerythrocytic development and growth of Babesia bovis, which causes cerebral babesiosis in cattle, under in vitro culture. However, administration of 10 µM SFC only in the medium did not inhibit parasite growth. ALA/SFC was efficacious in treating babesiosis in an experimental animal model with B. microti, which causes debilitating babesiosis in mice. Female BALB/c mice were infected with B. microti and administered a single oral dose of ALA/SFC combination daily in different concentrations for 30 days. Treatment with ALA/SFC at 4/0.4 mg/kg body weight significantly suppressed parasite development in the mice blood circulation and resulted in significantly lower parasitemia. Moreover, body weight loss in the mice has been improved significantly compared with the control group at the peak of parasitemia. Treated mice showed moderate decreases in red blood cell count, hemoglobin value, and hematocrit compared with those observed in the control group, indicating an effect in moderating progressive anemia. These findings suggested the potential of ALA/SFC to achieve symptomatic improvement against bovine babesiosis. Full article

According to the WHO there are more than 700,000 deaths every year involving vector-borne diseases such as malaria, dengue, Chagas disease, yellow fever and Japanese encephalitis. Aedes aegypti, the principal vector of the dengue virus, is of great concern in various parts of the world, especially in tropical and subtropical countries. Vector control through insecticide application is one of the best ways to control the disease’s transmission. Thus, insecticide resistance in Ae. aegypti poses a significant threat to public health worldwide. The use of plant natural product-based insecticides that are less harmful to the environment, and without known resistance development, constitutes an alternative to chemical insecticides. Given this, a methanolic extract from Vitex ovata plants was prepared and tested for its larvicidal effect against Ae. aegypti. A susceptibility test on Ae. aegypti larvae was conducted using the standard WHO method. Results showed that the methanolic extract of V. ovata had larvicidal activity against Ae. aegypti with LC₅₀ values of 2114 mg/L, and achieved 84% mortality with the highest concentration at 10,000 mg/L. This study showed that the crude extract of V. ovata bioactive molecules could be potentially developed as biolarvicides for Aedes mosquito vector control. This study recommends future research on using different solvents in the isolation of active ingredients from V. ovata, identification of phytochemicals with larvicidal properties, a toxicity study and lastly, an evaluation of the effectiveness of controlling Aedes in small-scale field trials for environmentally safe botanical insecticide intervention. Full article

The Anaplasmataceae family (order Rickettsiales) encompasses obligately intracellular bacteria of the genera Anaplasma, Ehrlichia, and Neorickettsia. Together with Coxiella burnetii (Coxiellaceae family, order Legionellales), these bacteria represent important causative agents of diseases in humans and animals. The scarcity of studies that investigated the occurrence of these agents in bats and their associated ectoparasites, emphasizes the need to achieve a better understanding of the role of these animals in the maintenance of such bacteria. Herein, 418 samples (133 blood, 135 spleen, and 150 ectoparasites) are collected from 135 non-hematophagous bats belonging to 12 species in a periurban area of Campo Grande city, Mato Grosso do Sul state, midwestern Brazil. In the results, 1.65% (7/418), 12.04% (50/418), and 13.63% (57/418) of samples are positive in PCR assays for Anaplasma spp. (16S rRNA gene), Ehrlichia spp. (dsb gene), and Neorickettsia spp. (16S rRNA gene), respectively. Anaplasma spp. and Neorickettsia spp. are detected in one (5.26%) Ornithodoros hasei tick larva. Ehrlichia spp. is detected in 14% of bat flies (represented by Megistopoda aranea, Trichobius costalimai, and Strebla hertigi), 6% of tick larvae (O. hasei), 12% of Spinturnicidae mites (represented by Periglischrus sp., P. torrealbai, and P. acutisternus), and 38% of Macronyssidae mites (Steatonyssuss sp.). The obtained sequences are observed to be similar to Anaplasma phagocytophilum (97.42–97.6% identified), Ehrlichia minasensis (96.73–100% identified), Neorickettsia risticii (96.7–100% identified), and Neorickettsia findlayensis (95.07–100% identified) by BLASTn analyses, and closely related to Ehrlichia ruminantium by phylogenetic analyses based on the gltA gene. No bat samples (blood/spleen) are positive in the qPCR assay for C. burnetii based on the IS1111 gene. The present work shows, for the first time, the occurrence of Anaplasmataceae in bats and associated ectoparasites (ticks, mites, and bat flies) from Brazil. Full article

Anti-piroplasm drugs currently on the market have proven toxicity to the host and parasite resistance. Plants are possible sources of novel drugs. Subsequently, a novel strategy should be used to find new anti-piroplasm agents that are both effective and safe. In the present study, we have evaluated the effect of turmeric (Curcuma longa) methanolic extract on the in vitro growth of Babesia (B.) bovis, B. divergens, B. caballi, and Theileria (T.) equi. The in vitro inhibitory effectiveness of turmeric was assessed using a fluorescence test. The enhancement in the in vitro inhibitory efficacy of turmeric when administrated in combination with diminazene aceturate (DA) was investigated using in vitro cultures of different piroplasm parasites. Turmeric reduced the in vitro growth of B. bovis, B. divergens, T. equi, and B. caballi with IC₅₀ values of 0.830 ± 0.078, 0.375 ± 0.055, 1.405 ± 0.575, and 0.720 ± 0.090 mg/mL, respectively. An amount of 1 mg/mL turmeric for B. bovis, 0.5 mg/mL turmeric for B. divergens, 1 mg/mL turmeric for T. equi, and 0.5 mg/mL turmeric for B. caballi exhibited 73.43%, 80.065%, 73.47%, and 47.375% inhibitions in the growth of the parasites, respectively. When turmeric was combined with DA, its in vitro inhibitory impact on bovine Babesia and equine Babesia/Theileria parasites was amplified. These findings show that a methanolic extract of turmeric could be a promising medicinal plant for the treatment of babesiosis, especially when administered in conjunction with DA. Full article

Cystic Echinococcosis (CE) is an endemo-epidemic disease in the Rio Negro Province, República Argentina. Due to the number of cases, the length of hospital stays after surgery and its associated mortality, it is a serious public health problem that generates high costs for the health system. Oriented towards its control, primary prevention activities have been carried out since 1980, based on the deworming of dogs and the vaccination of lambs; secondary prevention has consisted in the actively search for cases through serological or ultrasonographic screening; and tertiary prevention has been based on timely treatment, either by surgery or by medical treatment with albendazole. All these prevention activities have been carried out under the concept and strategies of the “One Health” model, through both inter-institutional and interdisciplinary work, as well as with the support, commitment and critical participation of the community. As a result, an important drop has been observed in the prevalence of CE in humans and in its lethality (0.5% in 1997–2020, no deaths in the last two years); moreover, an important decrease has been observed in costs to the health system, due to the reduction of hospitalizations and the number of surgeries. Full article