Setaria labiatopapillosa (Filarioidea, Nematoda) in Moroccan cattle: atypical localization and morphological characterization of females and microfilariae by light and scanning electron microscopy.

Filarioid nematodes are parasites of the tissues and tissue spaces of all vertebrates except fish. Females produce microfilariae that enter the host's blood circulation or skin and may cause ocular and neurological pathology, leading to important implications in veterinary and public health. The present work is the first investigation on Setaria labiatopapillosa conducted in Morocco to characterize the morphological features of both adult and microfilaria forms. Two adult female nematodes were found free in the thoracic cavity of a slaughtered 3.5-year-old (6 teeth) Moroccan enhanced cross-breed bull which was born and raised in Morocco. The worms were identified as S. labiatopapillosa by light microscope (LM) and scanning electron microscopy (SEM) on the basis of their characteristic features of the anterior and posterior parts of the worms. The two S. labiatopapillosa worms measured 90 mm and 105 mm in length and 0.55 and 0.64 mm in width, respectively. Microfilariae were detected in the fully developed eggs contained in the uterus of both nematodes. A detailed morphology of both the adult females and larvae of S. labiatopapillosa is described using LM and SEM. Although the origin of S. labiatopapillosa analyzed in the present study is unknown and there is currently no evidence that Setaria spp. have invaded Morocco, further surveillance is warranted to determine the incidence of setariasis, identify its vectors, and take appropriate measures to protect the livestock and cattle industry of the country.

Tabanids as possible pathogen vectors in Senegal (West Africa).

BACKGROUND: Species of the Tabanidae are potent vectors of human and animal diseases, but they have not been thoroughly investigated to date. In Senegal (West Africa), little information is available on these dipterans. Our objective in this study was to investigate Senegalese tabanids and their diversity by using molecular and proteomics approaches, as well as their associated pathogens. METHODS: A total of 171 female tabanids were collected, including 143 from Casamance and 28 from Niokolo-Koba. The samples were identified morphologically by PCR sequencing and by MALDI-TOF MS, and PCR analysis was employed for pathogen detection and blood-meal characterization. RESULTS: The morphological identification revealed four species concordantly with the molecular identification: Atylotus fuscipes (79.5%), Tabanus guineensis (16.4%), Chrysops distinctipennis (3.5%) and Tabanus taeniola (0.6%) (not identified by PCR). The molecular investigation of pathogens revealed the presence of Trypanosoma theileri (6.6%), Leishmania donovani (6.6%), Setaria digitata (1.5%), Rickettsia spp. (5.1%) and Anaplasmataceae bacteria (0.7%) in A. fuscipes. Tabanus guineensis was positive for L. donovani (35.7%), S. digitata (3.6%) and Anaplasmataceae (17.8%). Leishmania donovani has been detected in 50% of C. distinctipennis specimens and the only T. taeniola specimen. No Piroplasmida, Mansonella spp. or Coxeilla burnetii DNA was detected. In addition to humans (96.43%), Chlorocebus sabeus, a non-human primate, has been identified as a host of (3.57%) analysed tabanids. MALDI-TOF MS enabled us to correctly identify all tabanid species that had good quality spectra and to create a database for future identification. CONCLUSIONS: Tabanids in Senegal could be vectors of several pathogens threatening animal and public health. To fully characterize these dipterans, it is therefore necessary that researchers in entomology and infectiology employ molecular characterization and mass spectrometric techniques such as MALDI-TOF MS to analyse these dipterans in Senegal and West Africa.

Phylogenetic characterization of Setaria equina and its association with other filarids.

Molecular characterization studies on Setaria equina are limited. The present study aimed to characterize S. equina at the cytochrome c oxidase gene and to examine its phylogenetic relationships with other filarid species. Sequence analysis showed 100% nucleotide homology with an S. equina sequence from Italy (AJ544873). However, both sequences exhibited 7 nucleotide substitutions from a S. equina donkey isolate from Egypt (MK541847). Overall, S. equina formed a monophyletic sister group to Setaria tundra. All Setaria spp. examined formed a separate group on the phylogenetic tree that was related to corresponding Onchocerca spp. and Dirofilaria spp. clades. Human filarid worms-Brugia spp. and Wuchereria spp. grouped in a separate clade alongside Theilezia spp. Dipetalonema spp.-formed a separate group at the top of the tree.

First report of equine Setaria digitata (von Linstow 1906) infestation in Malaysia.

The occurrence of Setaria digitata in a horse is reported for the first time in Malaysia. An 8-year-old Thoroughbred cross mare was referred to the University Veterinary Clinic with the primary complaint of corneal opacity and excessive eye discharge. After initial treatment with Terramycin eye ointment, corneal opacity cleared partially to reveal a moving thread-like cylindrical worm in the anterior chamber of the eye. The parasite was successfully removed surgically, and examination under the light microscope revealed that the isolated worm (length = 45 mm) was a 5th stage larva of S. digitata based on morphological criteria. Confirmation of the species of the worm was through molecular methods. The 12S rRNA gene was PCR-amplified, and the purified amplicon was directly sequenced. Phylogenetic analyses revealed that the isolated roundworm showed 100% sequence similarity with that of S. digitata in NCBI GenBank database (Accession no.: KY284626.1). This report is the first confirmed case of equine ocular setariasis by S. digitata in Malaysia. The current study provides evidence that S. digitata is an etiological agent of ocular infection and its presence in Malaysia.

New findings of Setaria tundra and Setaria cervi in the red deer (Cervus elaphus) in Poland.

Our study aimed at examining the phylogenetic position of the newly-found Setaria nematodes obtained from the red deer (Cervus elaphus) based on sequences of the mitochondrial cytochrome c oxidase subunit 1 (COX-1). Alignment and phylogenetic analyses, as well as SEM microscopic analysis, revealed the presence of two Setaria species: S. cervi and S. tundra. Setaria tundra was noted in only one individual, a calf of the red deer, while S. cervi was observed in three stages, two hinds and one calf of the red deer. According to our knowledge, it is the first case of S. cervi in the red deer in Poland confirmed in molecular studies and also the first case of S. tundra infection in the red deer.

Filarial nematode (order: Spirurida) surveillance in urban habitats, in the city of Pécs (Hungary).

As part of the seasonal mosquito control activities in the city of Pécs (Baranya County, Hungary), a total of 1123 adult female mosquitoes belonging to 18 species (including the invasive species Aedes koreicus) were collected from human-inhabited areas, using CO2-baited traps, during two consecutive years. To survey the presence and prevalence of filarial parasites in these mosquitoes, we performed a molecular survey for filarial DNA, attempted by PCR using generic primers (COI), and followed by DNA sequencing. Filaroid nematode DNA was detected in 4% of investigated mosquito pools. Out of 410 pools, 9 pools of mosquitoes were positive for Dirofilaria repens (Aedes vexans, Aedes koreicus, Coquillettidia richiardii), and/or Dirofilaria immitis (Ae. vexans, Cq. richiardii), and further 8 pools were positive for Setaria tundra (Ae. vexans, Cq. richiardii). Our study provides novel insight for prevalence of filaroid nematodes in mosquitoes occurring in close proximity to humans, thereby highlights the possible human and veterinary health importance of these mosquito species, including the recently introduced invasive mosquito Ae. koreicus.

Characterization of the complete mitochondrial genome of Setaria digitata (Nematoda: Setariidae) from China.

Setaria digitata is a filarial parasite that causes fatal cerebrospinal nematodiasis in goats, horses and sheep, resulting in substantial economic losses to livestock farmers. In the present study, the complete mitochondrial (mt) genome of S. digitata from China was determined, characterized and compared with that of S. digitata from Sri Lanka. The identity of the mt genomes was 98.3% between S. digitata from China and Sri Lanka, and the complete mt genome sequence of S. digitata from China was slightly shorter (25 bp) than that from Sri Lanka. For the 12 protein genes, this comparison revealed sequence differences at both the nucleotide (1.4%) and amino acid (2.2%) levels. The present study determined the complete mt genome sequence of S. digitata from China, providing novel genetic markers for the study of the population genetics and molecular epidemiology of S. digitata in animals.

Molecular characterization of Setaria digitata from Mithun (Bos frontalis).

Mithun is a strongly built hill animal of Southeast Asia and plays an important role in the socio-economic and cultural life of the tribal population. Setaria digitata isolated from peritoneal cavity of mithun both from Arunachal Pradesh and Nagaland were characterized based on conserved region of 12SrDNA, 28SrDNA and ITS-2 and mitochondrial gene CoxI. Based on sequence analysis, it was found to be 99% similarity with Srilankan isolate of S. digitata.

Redescription of Setaria graberi Shoho in Troncy, Graber & Thal, 1976 (Nematoda: Filarioidea) based on specimens from Redunca arundinum (Bovidae) in South Africa.

The filarial onchocercid Setaria graberi Shoho in Troncy, Graber & Thal, 1976 is redescribed from the abdominal cavity of Southern reedbuck, Redunca arundinum (Boddaert), in South Africa, including illustrations and scanning electron micrographs of important morphological features. Morphometric data for this species are provided for the first time. Setaria graberi is characterised by the possession of bifid deirids, and females having a distinctly bulbous tail. The slightly raised peribuccal crown forms a dumbbell-shaped unit with the cephalic elevations in apical view; the dorsal and ventral elevations, spaced 73-115 µm apart in females and 71-93 µm in males, carry two well-separated tips each. In dorsoventral view, the cephalic elevations appear more or less rectangular with a slightly notched apex and are narrow in comparison to the width of the anterior end. They are triangular in lateral view. Four cephalic and four external labial papillae are arranged in a laterally elongated rectangle each. The species is distinguished from other Setaria Viborg, 1795 species that possess bifid deirids or occur in members of the same host genus. The presence of S. graberi in R. arundinum in South Africa constitutes a new host and geographic record.

Setaria tundra in roe deer (Capreolus capreolus)--new findings in Poland.

Setaria tundra is a filarioid nematode transmitted by mosquitoes, which is sporadically observed in Poland. Some ecological factors, such as the synurbisation of some wild ungulates and the climate changes observed in recent years, could affect the possibility of infection, especially with parasites transmitted by arthropod vectors. The study was conducted to evaluate the presence of Setaria sp. in roe deer populations in different environments. Parasitological dissections of 53 roe deer were performed. The animals were taken from the area of the Cracow agglomeration, and from arable and forest lands near the city. During the autopsy, nematode specimens (one to twelve per host) were found only in the abdominal cavity of roe deer from the urban area. All parasites were classified to Setaria tundra species on the basis of morphology and dimensions. The infection observed was probably associated with the specific environmental conditions of the urban area.

Molecular characterization and phylogenetic analysis of Setaria digitata of Sri Lanka based on CO1 and 12S rDNA genes.

The aim of the present research is to determine the phylogenetic position of Setaria digitata of Sri Lanka in the evolutionary tree of filarial worms. DNA sequences of portions of the mitochondrial genes cytochrome c oxidase subunit 1 (CO1) and small subunit ribosomal RNA (12S rDNA) were analysed. Intra-specific variation was observed in CO1 but not in 12S rDNA. Phylogenetic trees inferred from these two genes resembled one another in recognizing monophyly of Setaria. S. digitata and Setaria labiatopapillosa appear to be sister species.

Studies on the genus Setaria Viborg, 1795 in South Africa. III. Setaria thwaitei Mönnig, 1933.

Mönnig (1933) described Setaria thwaitei from a sable antelope, Hippotragus niger, the type host, as well as from roan antelope, Hippotragus equinus, and waterbuck, Kobus ellipsiprymnus. Yeh (1959) considered Setaria thwaitei to be synonym of Setaria hornbyi. Material collected from roan antelopes, sable antelopes and gemsbuck, Oryx gazella, from several localities in the north and south of South Africa, together with Mönnig's (1933) material, were re-examined. Measurements of the adult worms obtained in this study were compared with those in the original description of the species. Scanning electron microscopy of the anterior and posterior regions of the female worms confirmed S. thwaitei as a valid species.

Molecular assay for the identification of Setaria tundra.

We report the molecular characterization of the amplification products obtained by specific PCR experiments aimed to identify the 5S ribosomal spacer of Setaria tundra specimens isolated from roe deer (Capreolus capreolus) in north Italy, which represent the first record of the parasite in this country. Three different fragments of approximately 400, 800, and 1200 bp (base pairs) are produced. Sequence analyses showed that all three fragments share a very high level of similarity to 5S spacer sequences of some Setaria species and other filariae present in genebank. Based on these sequences, we were able to design species-specific PCR primers for the precise identification of S. tundra.

Studies on the genus Setaria Viborg, 1795 in South Africa. II. Setaria scalprum (Von Linstow, 1908) and Setaria saegeri (Le Van Hoa, 1961).

Setaria scalprum (Von Linstow, 1908) and Setaria saegeri (Le Van Hoa, 1961) are closely related filarid species that occur in the smaller antelope of Africa. Material previously collected from common dulker, Sylvicapra grimmia, steenbok, Raphicerus campestris and grysbok, Raphicerus melanotis, from several localities in the northern and eastern regions of South Africa was re-examined and measurements of adult worms were compared with those given in the original descriptions of the species. Scanning electron microscopy of the anterior and posterior regions of the female worms confirmed the validity of the two species. Differences in the postdeirid, ventral transverse bands and bosses on the cuticle of the male specimens were also observed. Setaria saegeri in common duiker and grysbok is a new parasite record for these hosts.

Studies on the genus Setaria Viborg, 1795 in South Africa. I. Setaria africana (Yeh, 1959).

Setaria africana (Yeh, 1959) is represented by two subspecies, Setaria africana africana Troncy, Graber & Thal, 1976 from giant eland (Taurotragus derbianus) from the Central African Republic and Cameroon and Setaria africana farchai Troncy, Graber & Thal, 1976 from bushbuck (Tragelaphus scriptus), also from the Central African Republic. Material collected from nyala (Tragelaphus angasii), bushbuck and kudu (Tragelaphus strepsiceros) from several localities in the eastern region of South Africa was re-examined. Measurements of adult worms confirmed the differences between the two subspecies and scanning electron microscopy showed that the deirids of S. africana africana are single whereas those of S. africana farchaiare double. Setaria africana farchaiis recorded for the first time in South Africa.