Distortion of the gizzard in Cyprus pigeons (Columba livia) associated with Hadjelia truncata infestation

Morphological, molecular, and histopathological studies on Hadjelia truncata from Columba livia domestica and its role as an environmental biological indicator

Pigeons are a cosmopolitan group of birds with abundant and large populations associated with human activities. This study focused on determining parasitic infections within domestic pigeons (Columba livia domestica). Forty-eight pigeons were examined for infections, of which 29.16% were infected with a nematode parasite, identified as Hadjelia truncata (Habronematidae), under the koilin layer of their gizzards. The population of nematodes in infected gizzards did not exceed 20 adult worms. DNA from the gizzard worms was extracted and subjected to PCR using primers that amplify the partial 18S rDNA and cytochrome C oxidase subunit I (COX I) regions. Identification of this parasite based on microscopic study revealed the presence of trilobed lips with cephalic papillae and amphidial pores, as well as other characteristic features. In males, spicules were unequal with the presence of six pedunculated pairs of caudal papillae (4 pre- and 2 post-anal) and a tail surrounded with caudal ala. In females, the vulva was a rounded aperture located in front of the posterior end of the esophagus and uteri, which was filled with numerous embryonated eggs. DNA Sequences from partial 18S rDNA were homologous to sequences obtained from H. truncata in GenBank with a high percentage of identity. DNA sequences from mitochondrial gene COX I, however, were unique, and they were the first sequenced for H. truncata, since no sequences for this taxon were previously available in GenBank. Histopathological examination revealed enlargement of infected gizzards in comparison to non-infected ones, with the presence of necrosis and interstitial infiltration in the koilin layer. Concentrations of heavy metals (Fe, Cu, Zn, Cd, Cr, and Co) were measured using inductivity-coupled plasma in tissues (liver, muscles, and gizzards) from infected and non-infected pigeons as well as their parasites. Results showed different affinities of metals to tissues. Recovered parasites can minimize element concentration from their pigeon tissues. In Saudi Arabia, this study was considered the first report identifying pigeon nematodes and evaluating of the effects of their pathogenicity on the animals' welfare, as well as their application as a useful tool for monitoring environmental pollution.

Histopathological changes in the upper digestive tract of pigeons infected with Hadjelia truncata

Thirty-five pigeons from ten different farms in Fars area, southern Iran were submitted for post mortem inspection. Based on the clinical observations and gross pathological examinations, all the birds showed severe weight loss, diarrhea and to some extent ventricular enlargement. Furthermore, all the cases demonstrated large numbers of nematodes attached to the mucosa and submucosa of the ventriculus. Parasitological examinations revealed that the recovered parasites were Hadjelia truncata. The histopathological changes showed necrosis of the mucosal cells with moderate infiltration of lymphocytes, macrophages, heterophils and eosinophils in the lamina properia and muscularis mucosa in the infected animals. Based on the parasitological and pathological findings it can be concluded that the nematode H. truncate could be assigned as a pathogenic agent in the upper tract of pigeons.

New insights into morphological features of Hadjelia truncata (Spirurida: Habronematidae), as revealed by SEM

Hadjelia truncata (Spirurida: Habronematidae) is a nematode found in the gizzard of several avian species. However, it has been reported pathogenic only in pigeons (Columba livia), in which it causes severe ventriculitis. Scanning electron microscopy (SEM) was used to study the morphological aspects of adult worms of this nematode in detail. Males and females measured 6.5-9 and 12-16.5 mm, respectively. The bodies were straight with moderate uniform thickness in both males and females, narrowing at the anterior end. The cuticle was striated transversely. The mouth was surrounded by two lateral trilobed lips, and the dorsal and ventral interlabia were present. The two cephalic papillae were present on each side lodged just behind the upper and lower bases of each lip. Around the mouth, a large amphid was seen on each lip. At the anterior end of both male and female worms, an excretory pore on the ventral side and a pair of lateral cervical papillae were observed. In the female, the vulva was located at the anterior end of the body. The lips of the vulva protruded above the body surface, and the bluntly rounded posterior end showed an anal pore and two subterminal phasmids. The posterior end of the males curved ventrally, with large caudal alae supported by four pairs of stalked precloacal papillae, a single medial precloacal papilla, two pairs of postcloacal papillae, and a cluster of small papillae on the caudal extremity. Spicules were unequal and dissimilar.

Parasitic ventriculitis caused by Hadjelia truncata in California rock pigeons (Columba livia)

Severe ventriculitis and emaciation caused by the infestation of the nematode Hadjelia truncata occurred in meat-type breeder rock pigeons (Columba livia) in southern and central California. Hadjelia truncata can infest several species of birds, although it has only been reported as pathogenic in pigeons. The factors that contribute to H. truncata pathogenicity are not known. The gross and microscopic pathology caused by the infestation of H. truncata in the ventriculus of pigeons and its morphological identification are presented.