Volume 57 (2020): Issue 4 (December 2020)

Hymenolepis nana is the most common cestode reported in humans worldwide. It is prevalent among children in the tropics and subtropics, particularly in rural poor communities where sanitation is inadequate or lacking. This cross-sectional study aims to determine the prevalence and significant risk factors of H. nana infection among children in rural Yemen. Faecal samples were collected from 498 children and screened for intestinal parasites by using wet mount, formalin-ether concentration and Kato–Katz techniques. A pretested questionnaire was used to collect demographic, socioeconomic, housing condition, and personal hygiene information. Overall, 77.5 % (386/498) of the children were found to be infected by at least one intestinal parasite species. The overall prevalence of H. nana was 17.5 % (87/498). Multivariate analysis confirmed that an age of < 6 years (adjusted odds ratio [AOR] = 4.28; 95 % (confidence interval [CI] = 2.04, 8.98), presence of other family members infected with H. nana (AOR = 2.48; 95 % CI = 1.45, 4.24), living in the highlands (AOR = 2.87; 95 % CI = 1.56, 5.26), living in a house without improved toilet facilities (AOR = 2.19; 95 % CI = 1.23, 3.88), not washing vegetables before consumption (AOR = 2.11; 95 % CI = 1.06, 4.19), and not washing hands after defecation (AOR = 1.88; 95 % CI = 1.08, 3.27) were the key factors significantly associated with H. nana infection among the studied children. In conclusion, H. nana is prevalent among children in rural Yemen, particularly among preschool-aged children. Thus, an integrated and effective programme to control intestinal parasitic infections should include preschool-aged children. Such a programme should focus on providing health education on hygienic practices, providing adequate sanitation and improved sources of drinking water, and screening and treating other infected family members.

Protostrongylids, small nematode lungworms, are an integral part of the wild ruminant helminth community, which can damage animals’ health when they are held in captivity or semi-captive conditions. The Sahelo-Saharan antelope species dorcas gazelle (Gazella dorcas), the scimitar-horned oryx (Oryx dammah), and the addax (Addax nasomacculatus), reintroduced to Souss-Massa National Park in Morocco, could be host to many species of Protostrongylids. This study was conducted from January to July 2015 to identify infecting parasite species, and determine their prevalence and abundance in all three antelope species. A total of 180 individual fecal samples were collected, morphologically examined by the Baermann technique, and molecularly identified by PCR amplification and sequencing of the second internal transcribed spacer region of the rDNA (ITS-2).

Two parasite species were found in the three antelope populations: Muellerius capillaris and Neostrongylus linearis. The prevalence scores recorded for M. capillaris were 98.40 % in the addax, 96.70 % in dorcas gazelle, and 28.40 % in the oryx. The prevalence rates of N. linearis were 60 % in the addax, 23.40 % in dorcas gazelle, and 90 % in the oryx. Excreted larvae were quantified by LPG (larvae per gram) counting: for M. capillaris, the LPG mean values were 92.94 in the addax, 133.09 in dorcas gazelle, and 1.48 in the oryx; and for N. linearis, the LPG mean values were 6.02 in the addax, 1.37 in dorcas gazelle, and 32.81 in the oryx. These findings indicate that the three species of antelopes are infected with Muellerius capillaris and Neostrongylus linearis to varying degrees in intensity and prevalence.

The aim of this study was to investigate the difference in Fecal Egg Counts (FEC) with regard to group size, age, sex and body condition of wild free-roaming Przewalski’s horses in the Chernobyl Exclusion Zone (Ukraine), across different seasons, over a five-year period (2014 – 2018). We hypothesized that horses from larger group sizes would have higher faecal egg counts (FECs). The relationship between FECs and the year and season of sample collection, and age, sex and group size of the horses was analyzed. Generalized linear model using positive strongylid FEC`s as a variable response, was used to investigate the differences in FECs between the groups.

Nematode (Strondylidae, Parascaris spp., Habronematidae) and cestode (Anoplocephalidae) eggs were also identified. Stronglyids were the most prevalent helminth egg, and had the highest FECs.

The model for egg counts of strongylids showed that season and group size of horses were statistically significant. Presence of strongylid eggs was not dependent on age and sex of horses. We suggest that this could be a result of parasite transmission between individuals and groups in places were animals aggregate around water sources or collective farms.

Results obtained in this current study broaden the knowledge of gastrointestinal parasites in free-roaming horses under wild natural conditions.

Respiratory capillariosis is a widely distributed zoonotic parasitic disease caused by the nematode Capillaria aerophila (Trichocephalida, Trichuridae) that commonly infects wild carnivores but also cats and dogs. This retrospective study aims to describe cases of respiratory capillariosis in cats from the city of Belgrade, Serbia. Between 2015 and 2019, a total of 155 pet cats with or without respiratory symptoms were submitted to physical examination and parasitological examination of the feces. All cats lived indoor but had free access to outdoor. In suburban settlements, wild carnivores commonly share their living environments with owned cats and dogs. It can be assumed that more intense urbanization spreading into the natural habitats of will carnivores creates the opportunity for closer and more frequent contacts between the population of cats and feral carnivores which might increase the risk of feline contamination. The findings confirm the existence of capillaries in cats in urban areas of the city of Belgrade, contribute to a better understanding of the epidemiology of this nematode and warn that, because of close contacts between cats of pets and humans, capillaries can cause human infection.

Biomphalaria alexandrina snails have received much attention due to their great medical importance as vectors for transmitting Schistosoma mansoni infection to humans. The main objective of the present work was to assess the efficacy of miltefosin a synthetic molluscicidal drug and artemether a natural molluscicidal drug. The correlation between immunological and histological observations from light and electron microscopy of the hemocytes of B. alexandrina post treatment with both drugs was also evaluated. LC₅₀ and LC₉₀ values were represented by 13.80 ppm and 24.40 ppm for miltefosine and 16.88 ppm and 27.97 ppm for artemether, respectively. The results showed that the treatment of S. mansoni-infected snails and normal snails with sublethal dose of miltefosine (LC₂₅₌8.20 ppm) and artemether (LC₂₅₌11.04 ppm) induced morphological abnormalities and a significant reduction in hemocytes count.

We recorded the metazoan parasite communities in three endemic cichlids (Chiapaheros grammodes, Vieja breidohri and V. hartwegi) collected between November 2008 and July 2009 in the upper Grijalva River Basin (GRB), Chiapas, Mexico. In total, 6,287 individual parasites belonging to 18 taxa (1 monogenean, 6 digeneans, 1 cestode, 4 nematodes, 2 acanthocephalans, 1 hirudinean, 2 copepods and 1 pentastomid) were found. Eleven metazoans were adult forms and 7 larvae; moreover, 14 were endoparasites and 4 ectoparasites. Sixteen parasite taxa represent new geographical and host records. The helminth community in the three cichlids was characterized by higher number of generalists than specialists, as well as a higher proportion of autogenics than allogenics. The metazoan parasites showed prevalence and mean abundances moderate to high. The infracommunities and component community of metazoan parasites had low diversity, richness, and number of individuals and are similar to those reported for other cichlids in Southeastern Mexico, characterized by the presence of typical parasites of cichlids, with a high number of digeneans and generalist parasites. We report the introduced Asian parasitic copepod Neoergasilus japonicus parasitizing endangered or threatened endemic cichlids in the upper GRB. This copepod have been widespread in other freshwater fish species, mainly in Asia (China, India, Japan, Russia, Taiwan), Europe (France, Hungary, Italy, Turkey), and America (Cuba, Mexico, Peru, United States).

The mature spermatozoon of Khawia armeniaca, a monozoic caryophyllidean parasite of templar fish Capoeta capoeta sevangi (De Filippi, 1865) from the Lake Sevan, Armenia, has been studied using transmission electron microscopy and cytochemical technique of Thiéry (1967) for the first time. The mature spermatozoon of K. armeniaca consists of a single axoneme with the 9+‘1’ trepaxonematan structure, cortical microtubules and nucleus which are situated parallel to the longitudinal axis of the spermatozoon, and a moderately electrondense cytoplasm with glycogen particles. The cortical microtubules are arranged in one continuous semicircle beneath the plasma membrane in Region II and anterior part of Region III of the mature spermatozoon. The two opposite rows of cortical microtubules are observed in the remaining nuclear and at the beginning of the postnuclear part (Regions III, IV) of the male gamete The number of cortical microtubules is remarkably variable in the spermatozoa of various Khawia species. K. armeniaca exhibits the highest number of cortical microtubules in comparison with K. sinensis and K. rossittensis. Glycogen was detected in the cytoplasm of prenuclear (II), nuclear (III) and postnuclear (IV) regions with different ultrastructural organization of the mature spermatozoon of K. armeniaca. Variations of sperm ultrastructural characters within caryophyllideans and other cestodes are discussed.

In order to investigate the vertical distribution of soil nematode community under a playa area in the Nizzana inter-sand dune area in the north-western Negev Desert of Israel, soil samples were collected from 0 – 10, 10 – 20, 20 – 30, 30 – 40, and 40 – 50 cm depths in the playa and loessial plain area (as control) during the dry and wet seasons. Each of soil samples was determined for soil moisture, organic matter concentration, electrical conductivity, and nematode community structure and biodiversity. The results revealed that soil moisture, organic matter, electrical conductivity, total nematode abundance and trophic groups were significantly influenced by sampling positions (P < 0.0001) and depths (P < 0.05) and significant interaction effect of position and depth (P < 0.05) was also found. Total number of nematodes in the playa area ranged from 1 to 15 individuals per 100 g dry soil, whereas they ranged from 60 to 631 individuals per 100 g dry soil in the loessial plain area. The greatest nematode number was found in 0 – 10 cm soil depth and the lowest nematode number was found in 40 – 50 cm soil depth. Total number of nematodes, bacterivores, fungivores, plant parasites and omnivores-predators were significantly (P < 0.05) greater in the loessial plain area than that in the playa area in all sampling depths under the dry and wet seasons. Total thirteen genera were found in the playa area, with Acrobeloides as the dominant genus, whereas there were fifty-five genera, with Acrobeles as the dominant genus in the loessial plain area. Nematode ecological indices, such as fungivores/bacterivores ratio (F/B), nematode channel ratio (NCR), trophic diversity (T), Shannon Index (H’), genus dominance (λ), species richness (SR), maturity index (MI), modified maturity index (MMI), Enrichment Index (EI) and Structure Index (SI) were significantly (P < 0.01) differentiated between sampling locations. As conclusion, soil free-living nematode inhabited mostly the upper soil layers (0 – 20 cm) and the number of nematode had gradually decreasing trend with soil depths increasing in the playa area. Moreover, each soil layer had a little nematode abundance and community diversity in the playa area in contrast to loessial plain area during the dry and wet seasons. Sampling sites and depths significantly effected on soil properties, nematode abundance and trophic groups, but nematode ecological indices were affected only by sampling sites.

Soil treatments with formulated plant biomasses or waste materials can be an effective alternative to green manure crops for a sustainable management of root-knot nematode infestations. The suppressive performance of soil amendments with three commercial formulations of defatted seed meal from Brassica carinata, dry biomass of Medicago sativa and pressed pulp from Beta vulgaris was comparatively evaluated on the root knot nematode Meloidogyne incognita both on potted and field tomato (cv. Regina) trials. Products were applied at rates of 10, 20, 30 or 40 g/kg and 20 and 40 T/ ha soil in pots and field, respectively. Soil non treated or treated with the nematicide Oxamyl were used as controls in both experiments. Amendments in potted soil significantly reduced M. incognita infestation on tomato roots compared to both the untreated control and treatment with Oxamyl, also increasing tomato plant growth up to the 30 g/kg soil rate. At the end of the field tomato crop, soil population density of M. incognita resulted significantly reduced by all the tested treatments, whereas tomato yield was significantly higher than the untreated control only at the lowest amendment rate. Soil amendments with the materials tested in this study demonstrated to be a potential additional tool for a satisfactory and safe management of root-knot nematodes.

The larvae of the genus Baylisascaris can cause larva migrans in mammals and birds. This study investigated the larval migration of Baylisascaris potosis, the roundworm of kinkajou (Potos flavus), in chickens and the associated clinical manifestations of the host. Thirty-six 3-week-old chickens divided into 6 groups were orally inoculated with 3,000 B. potosis eggs/chick. Each group of chicken was necropsied at days 1, 2, 3, 7, 30 and 90 PI (post inoculation), and the number of larvae in various organs were counted until day 90 PI. No clinical signs were observed in chickens during the study. Larvae were detected from the liver, lungs or breast-muscles of 13/36 (36.1%) chickens. The mean total number of larvae in the liver, lungs and breast-muscles at days 1, 2, 3, 7, 30 and 90 PI were 0.34, 0.17, 1.66, 1.01, 0.17 and 0, respectively. No larvae were found in the brain, eyes, hid-limb muscles, heart, kidneys and spleen. Although infectivity of larvae in egg-inoculated chickens was low, the present study demonstrated that B. potosis larvae can migrate in chickens tissues up to day 30 PI. The result suggests that chickens can serve as a paratenic host for B. potosis and may underline a public health importance of B. potosis infection as a potential foodborne disease in humans.

Leptodactylus petersii is a species of anuran found in both terrestrial and aquatic habitats and occurs from South America to southern North America and the West Indies. Studies involving the fauna of anuran parasites offer complementary information related to ecology. Thus, since there are few studies on the natural history of this species, this research aims to analyze the diet and the presence of endoparasitic helminths of Leptodactylus petersii from the state of Amapá, Brazil. We found 10 different taxonomic categories of prey in stomach contents, with the categories Hymenoptera (Formicidae) with 32.26 % (n = 12) being the most representative. Among the 12 individuals of L. petersii that were analyzed for helminth parasites, 83.3 % were infected with at least one species of helminths allocated to Phylum Nematoda. Our results report a new occurrence site for Rhabdias breviensis, originally described for Leptodactylus petersii in the state of Pará, as well as the second report of Ortleppascaris sp. in Brazil.

The dagger nematodes of the longidorids can cause diseases of various agronomic and horticultural crops, and are consisted of more than 260 valid species. In a forest survey of ecotypes of longidorid nematodes, from the root zone soil of Brant’s oak, (Quercus brantii Lindl.) and hawthorn (Crataegus aronia L.) trees, three species of Xiphinema americanum group namely Xiphinema pachtaicum, X. oxycaudatum and X. plesiopachtaicum were collected and studied based on their morphological and morphometric characters. X. pachtaicum is prevalent Xiphinema species in Iran. In this paper additional data for X. oxycaudatum and X. plesiopachtaicum species are presented. X. plesiopachtaicum is a new record for nematode fauna of Iran.