Monthly variations of Rhinoestrus spp. (Diptera: Oestridae) larvae infesting donkeys in Egypt: Morphological and molecular identification of third stage larvae

Morphomolecular characterization of Strongylus vulgaris isolated from donkeys with special references to histopathological study on the affected organs

Equine gastrointestinal tract is infected with Strongylus vulgaris (S. vulgaris) which is highly pathogenic parasite for its harmful effect on cranial mesenteric artery during its migration. So, this study was applied for identification of S. vulgaris in donkeys ultramorphologically and molecularly. In addition to, detection of the pathological effect of larval stage of S. vulgaris on the mesenteric arterial system using histopathology and immunohistochemistry. During the period from September to December; 2019, 60 male and 20 female donkeys at the Giza Zoo was postmortem examined. S. vulgaris adults and larvae were collected from the large intestine and cranial mesenteric arteries (CMAs), respectively. Ultramorphological examination of the collected adults was done using scanning electron microscope (SEM). DNA was extracted from 5 larvae and 6 adults for further conventional PCR studies and sequencing of the internal transcriped spacer 2 (ITS2) gene. The ITS2 gene were amplified and showed bands at 148 base pair (bp). The ITS2 gene nucleotide sequences of all isolates were aligned using Basic Local Alignment Search Tool (BLAST). Histological sections of S. vulgaris affected mesenteric arteries exhibited the presence of the parasite larvae either in the lumen with thrombus formation or attached to the intima. Most of the detected inflammatory cell populations were CD68-positive cells. From these results, it can be concluded that the ribosomal spacers genes could be used as markers for Strongylus species identification in eggs collected from equine feces as a beneficial method of diagnosis. Also, it could be important in disease surveillance, improving preventive measures and developing an effective control strategy.

Evaluation of immune responses and oxidative stress in donkeys: Immunological studies provoked by Parascaris equorum infection

This study aimed to assess the effects of Parascaris equorum (P. equorum) in infected donkeys through evaluation the oxidative stress and different gene parameters in infected tissues. Fifty donkeys were examined in Giza Zoo abattoir from the period of January to March 2021. Blood and sera samples were collected from each examined donkey. P. equorum were subjected for identification through scanning electron microscope study and the infected tissues were subjected into gene expression analysis using two genes; interleukin 1β (IL1- β); and pro-inflammatory cytokines (TNF-α) with assessment of the antioxidant and free radicals released from the animals during the infection. Eighteen donkeys were positive for P. equorum adult or larvae by postmortem examination of the intestine and abdomen with prevalence rate of 36 %. The examined infected donkeys with P. equorum showed significantly higher of Total antioxidant capacity (TAC) levels and the serum malondialdehyde (MDA) 2.45 ± 0.53 than that in non-infected control donkeys. The levels of AST enzyme were 278.54 ± 0.45 while ALT enzyme was 14.97 ± 0.87 which was significantly higher than that of control negative donkeys. The infected donkeys with P. equorum showed significantly upregulation of the TNF-α and IL-1β which classify according to number of collected worms. The P. equorum infected donkeys exerted at least 100 eggs of parasite in feces. The fecal egg count was marked decreased after treatment with moxidectin. Moxidectin is considered a novel active ingredient that has a marvelous result with high persistency and protection for long time, in addition to, broad spectrum activity and low or no resistance. We recommend the periodical deworming with different molecules as more economic and lifesaving over a single treatment every 12 months parallel with parasitic testing.

Morphological and molecular characterization of Ascaridia columbae in the domestic pigeon (Columba livia domestica) and the assessment of its immunological responses

Parasitism is a divesting problem that is frequently overlooked and may result in severe prominent clinical manifestation. This study aimed to investigate the seasonal and sexual prevalence of the gastrointestinal nematode Ascaridia columbae (A. columbae) infection among domestic pigeons in Giza governorate, Egypt, during the period from 2020 to 2021. One hundred and sixty suspected pigeons were clinically investigated. Blood & tissue samples were collected from infected birds to estimate serum zinc concentration, malondialdehyde (MDA), and nitric oxide levels. As well as tumor necrosis factor-alpha (TNF-α), interleukin 1β (IL1β) activity, and histopathological examination were estimated; also, worms were collected for morphological identification using electron microscope (SEM) and molecularly identified using polymerase chain reaction (PCR), further sequenced, and submitted in GenBank with accession number MZ343369. The average ascarid (length × breadth) were 72.4 ± 3.3 µm (70.5 - 79.9 µm) × 39.9 ± 2.5 µm (37.6 - 42.3 µm). The distinguishing morphological characteristics that have been noticed in ascarid worms were creamy white, cylindrical worm with triradiate lips with wide cephalic alae extending on both the lateral sides and filariform esophagus. In males, spicules were almost equal with the presence of precloacal chitinous-rimmed sucker. The prevalence of A. columbae infection was (63.1%) with a higher incidence in females (79.2%) than males (46.1%). The highest seasonal prevalence was observed in winter (92.5%), followed by summer and spring (87.5% and 55%), respectively while, the lowest prevalence was observed in autumn (17.5%). The intensity of worms in the infected intestine varied from 5 to 120 adult worms. The histopathological examination revealed the presence of chronic diffuse moderate catarrhal enteritis with roundworms in the lumen. Infected birds showed a significant increase in nitric oxide and MDA levels while serum zinc levels were lowered in infected pigeons. Infected pigeons revealed a marked increase in IL1-β and TNFα than apparently healthy ones.

The family Oestridae in Egypt and Saudi Arabia (Diptera, Oestroidea)

All known taxa of the family Oestridae (superfamily Oestroidea) in both Egypt and Saudi Arabia are systematically catalogued herein. Three oestrid subfamilies have been recorded in Saudi Arabia and/or Egypt by six genera: Gasterophilus (Gasterophilinae), Hypoderma, Przhevalskiana (Hypodermatinae), Cephalopina, Oestrus, and Rhinoestrus (Oestrinae). Five Gasterophilus spp. have been recorded in Egypt, namely, G. haemorrhoidalis (Linnaeus), G. intestinalis (De Geer), G. nasalis (Linnaeus), G. nigricornis (Loew), and G. pecorum (Fabricius). Only two of these species have also been recorded in Saudi Arabia, namely: G. intestinalis (De Geer) and G. nasalis (Linnaeus). The subfamily Hypodermatinae is represented in the two countries by only four species in two genera, namely, H. bovis (Linnaeus) and H. desertorum Brauer (in Egypt only), and H. lineatum (Villers) (in Saudi Arabia only) and Przhevalskiana silenus (Brauer) (in both countries). The subfamily Oestrinae is represented by two widely distributed species in both countries, namely, C. titillator (Clark) and O. ovis (L.), in addition to another species represented in Egypt only, R. purpureus (Brauer). For each species, synonymies, type localities, distribution, Egyptian and Saudi Arabian localities with coordinates, and collection dates are presented.

First reports of nasal and traumatic myiasis infection in endangered Przewalski's horses (Equus ferus przewalskii)

Myiasis has great economic and medical importance. However, myiasis in wildlife that is caused by oestroid flies is relatively rarely recorded compared with that in humans and domestic animals. Recently, during our research on the conservation of Przewalski's horse (PH), we observed two new records of oestroid flies parasitizing wildlife in China. The first is the horse nasal bot fly, Rhinoestrus sp. (Diptera: Oestridae), found in a dead PH from Kalamaili Nature Reserve. One morphotype (R. purpureus-like) was identified. The second is the Wohlfahrt's wound myiasis fly, Wohlfahrtia magnifica (Schiner, 1862) (Diptera: Sarcophagidae), which was collected from an open wound of a PH in the Wild Horse Breeding Research Centre. These observations extend the records of known hosts of these two oestroid myiasis agents. To the knowledge of the authors, infestation by Rhinoestrus and Wohlfahrtia larvae causing myiasis in wildlife has not been reported in China previously.

The prevalence of Gasterophilus intestinalis (Diptera: Oestridae) in donkeys (Equus asinus) in Egypt with special reference to larvicidal effects of neem seed oil extract (Azadirachta indica) on third stage larvae

Gasterophiline larvae are of veterinary and medical importance caused specific equine intestinal myiasis. Gasterophilus intestinalis (Botfly larvae) had a wide geographical distribution. The present study explores the prevalence rate of G. intestinalis 3^rd stage larvae in Egypt from January- December 2017; besides, in vitro trials to control of this larvae and evaluation of this trial using Scanning Electron Microscope (SEM) and histopathology of treated larvae. In the present study, the 3^rd larval stage of G. intestinalis was found in clusters in the epithelium of the investigated stomach and infested with prevalence rate 97.2%. The highest collected numbers of larvae were found in two months; March and August (570 & 520 larvae) and lowest numbers (200 larvae) were collected in October, November, and December. The calculated LC₅₀ and LC₉₀ values of neem seed extract were 707.9 ppm and 1090.7 ppm. The different alteration was recorded after exposure to oil extract which showed some destruction on cuticle surface as folded and corrugated cuticle, destruction of maxillae with pits on its surface, disfigure and irregularity of cephalic spines. Histopathology of exposed G. intestinalis larvae showed different changes as thinning of cuticle at the different level (exocuticle, endocuticle, cell layers), degeneration of epithelial cells of the gut and different degree of necrosis was described. Life cycle of G.intestinalis was followed up after treatment with neem seed extract.

The prevalence and intensity of external and internal parasites in working donkeys (Equus asinus) in Egypt

Aim

This study aims to record and update the prevalence and intensity of external and internal parasites in working donkeys (Equus asinus) in Egypt during the period from January to December 2017.

Materials and Methods

A total of 120 donkeys (10 donkeys each month) were examined at Giza zoo abattoir through bimonthly visits. The examined donkeys were obtained from five governorates (Giza [20], Fayoum [40], Beni Suef [30], Monofia [20], and Assiut [10]). The animals were grouped according to age and sex.

Results

All examined donkeys were positive with at least one internal or even external parasitic species. The overall prevalence rate was 100%. A total of 11 helminths species (10 nematodes and 1 metacestode); 7 protozoal and 7 arthropod species were collected. The number of each parasite and intensity of infection with regard to age and sex was recorded.

Conclusion

All examined donkeys were infected with parasites with an overall prevalence of 100%. So, we recommended following up and continuous treatment of such diseased animal.

Ultramorphological and molecular characteristics of the larval stages of the horse nasal-myiasis fly, Rhinoestrus sp. (Diptera: Oestridae) from Mongolian horse in China

Rhinoestrus sp. (Diptera: Oestridae) is an economically important parasite that can cause severe nasal myiasis in equids and can also affect humans. The ultrastructure of all Rhinoestrus sp. larval instars from Mongolian horse was examined by light and scanning electron microscopy to characterize the features of Rhinoestrus. The structure of the anterior region, posterior region, and the spines of the third segment was analyzed for 10 specimens in each larval stage. Additionally, 34 third-instar (L3) larvae of Rhinoestrus sp. from Mongolian horse were subjected to molecular characterization by polymerase chain reaction (PCR). Partial sequencing of the mitochondrial cytochrome oxidase subunit I gene (COXI) was performed. Phylogenetic relationships for Rhinoestrus sp. from Mongolian horse were reconstructed based on COXI sequences and COXI homologs from 12 oestrid species available in GenBank, and inter- and intraspecies variations in nucleotide sequences were analyzed. The cephalopharyngeal skeleton of Rhinoestrus sp. from Mongolian horse at immature stages was composed of "H"-shaped hypopharyngeal sclerites and "Y"-shaped pharyngeal sclerites. Pairs of papillary sensillae in the cephalic region maintained the same number and location in all three instars, but the third instar additionally included two pairs of verruciform sensillae. COXI sequences of Rhinoestrus sp. larvae collected from Mongolian horses were separated from those of Cephenemyia sp. and other species of Rhinoestrus (R. phacochoeri and R. usbekistanicus). Our sequence analyses demonstrate that all samples greatly resembled Rhinoestrus purpureus but were not R. purpureus. Further studies will be needed to confirm the existence of a new species. The pairs of papillary sensilla in the cephalic region retained the same number and location in all three instars, but included two pairs of verruciform sensilla in the third-instar larvae collected from Mongolian horses were more closely related to those of Oestrus ovis and Pharyngomyia picta.