A morphological study of the oral cavity, pharyngeal cavity and oesophagus of the Nile crocodile, Crocodylus Niloticus (Laurenti, 1768)

In view of the paucity of detailed information in the literature relevant to the upper digestive tract of the Nile crocodile, this study describes the morphological and histological features of the oral cavity (gingivae, palate and tongue), pharyngeal cavity and oesophagus of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768) using light microscopy. The findings, which were supplemented by scanning electron microscopy, were compared with published information. The ciliated component of the oesophagus was also examined using transmission electron microscopy. The oral cavity had the form of a triangle and was dorso-ventrally flattened. The dorsal limit was formed by the palate and the ventral limit by the broad-based tongue. The close proximity of the tongue and palate severely limited the space within the cavity. The caudal border of the cavity was formed by the dorsal and ventral components of the gular valve. The epithelium of the palate, gingivae and tongue was stratified squamous in nature and appeared lightly keratinised. Specialised epithelial structures in the palate, gingivae and tongue, revealed by both light microscopy (LM) and scanning electron microscopy (SEM), bore characteristics resembling structures responsible for pressure and taste reception. Glandular tissue in the tongue was arranged in a triangular formation in the posterior region and displayed morphological features ascribed to salt secreting glands described in other Crocodilia. There were no palatine glands in the oral region of the palate, except that the oral surface of the dorsal gular fold contained branched tubular mucus secreting glands. The pharyngeal cavity was also dorso-ventrally flattened and was bordered rostrally by the flaccid dorsal gular fold, which displayed a median apical notch, and the ventral gular fold, which was supported internally by the broad rostral tip of the basihyal plate (hyaline cartilage). In the occluded mouth, the dorsal gular fold and the more rostrally positioned ventral component of the gular valve isolated the pharyngeal cavity. This arrangement is essential in preventing the crocodile from drowning (flooding of the pharyngeal cavity) while capturing prey. The roof of the pharyngeal cavity was characterised by the opening to the internal nares (an extension of the nasal passage from the external nares), the fibrous Eustachian plug sealing the common opening to the paired Eustachian ducts and a nodular tonsillar region, which was situated caudo-laterally to the Eustachian plug. Throughout this region, the epithelium was typically ciliated with goblet cells. However, the tonsillar nodules displayed regions of partial or no ciliation on their surface. SEM and stereomicroscopic observations showed fine longitudinal mucosal folding throughout the pharynx the distension of which, together with the large capacity for mucus production (produced by intraepithelial glands and mucus secreting glands), would facilitate the swallowing of large chunks of food in the living state. The ventrally situated laryngeal mound containing the slit-like glottis also displayed longitudinal folds and a ciliated epithelium. Anatomically, the oesophagus could be divided into two clear regions. The cranial, approximate two-thirds appeared broad and flabby. At the tracheal bifurcation, the oesophagus narrowed significantly and indicated a greater muscular content, confirmed by light microscopy. LM and SEM examination of the oesophagus, however, revealed three regional components, viz., the cranial, mid- and caudal regions. In the cranial region, the epithelium was densely ciliated with intervening goblet cells being present. In the mid-region the ciliated component decreased with a concomitant increase in the goblet cell component. In the caudal region there was a further decrease in the number of ciliated cells and a higher concentration of goblet cells. Transmission electron microscopy (TEM) of the ciliated component of the oesophagus showed typical ultrastructural features of both the ciliated and goblet cells.Dissertation (MSc (Veterinary Science))--University of Pretoria, 2002.Anatomy and Physiologyunrestricte

Oribatid mites (Acari, Oribatida) as intermediate hosts of tapeworms of the Family Anoplocephalidae (Cestoda) and the transmission of Moniezia expansa cysticercoids in South Africa

Six species of adult oribatid mites (Galumna racilis, Kilimabates pilosus, Kilimabates sp., Scheloribates fusifer, Muliercula ngoyensis and Zygoribatula undulata) and two immature stages belonging to the superfamilies Galumnoidea and Ceratozetoidea were isolated from a lawn (mixed Pennisetum and Cynodon spp.) at Onderstepoort Veterinary Institute, South Africa. The mites were subsequently used in an infection trial using Moniezia expansa eggs. Tapeworm cysticercoids were recovered in G. racilis, K. pilosus, Kilimabates sp., S. fusifer, M. ngoyensis and Z. undulata, as well as in immatures of Ceratozetoidea. The percentage of infected mites was 7.6, 6.3, 16.4, 66.7, 57.1, 60.0 and 46.7%, respectively. Immatures of Galumnoidea did not become infected. The highest number of cysticercoids isolated from one individual was six from an adult S. fusifer.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.F. Kleine Bursary of the Onderstepoort Veterinary Institute.mn201

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 bush buck ( 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 reexamined. 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 farchai are double. Setaria africana farchai is recorded for the first time in South Africa.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

A scanning electron-microscope examination of the scolex of Houttuynia struthionis

A scanning electron-microscope examination of the scolex of Houttuynia struthionis, a cestode of ostriches, was undertaken in order to study its surface structure. The scolex differs from those of other subfamilies in the family Davaineidae in that it does not have scale-like spines covering the base of the rostellum. Instead, the base is covered with small hooks resembling the larger rostellar hooks in shape.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat X Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Description of Aegyptianella botuliformis n. sp. (Rickettsiales: Anaplasmataceae) from the helmeted guineafowl, Numida meleagris

Aegyptianella botuliformis n. sp. (Rickettsiales: Anaplasmataceae) isolated from helmeted guineafowls Numida meleagris from the Kruger National Park is described. The rickettsia occurs within a membrane-bound vacuole in the cytoplasm of erythrocytes with up to 8 organisms in a mature inclusion. The initial body resembles that of Aegyptianella pullorum. The tightly packed, sausage-shaped intermediate forms are a distinctive morphological feature, seen as irregular, pleomorphic forms under light microscopy. While more larvae and nymphs of Amblyomma hebraeum and Amblyomma marmoreaum were found on the birds than larvae of an Argas sp., it is believed that the latter are the vectors of A. botuliformis n. sp. In addition to the Kruger National Park, positive blood smears were obtained from guineafowls at other localities in the Transvaal.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.Foundation for Research Development.mn201

An investigation into the toxic principle in eggs of the tick Amblyomma hebraeum

A purification procedure involving iso-electric focusing by means of which a toxic principle may be obtained in a pure form from crude egg extracts of Amblyomma hebraeum is described. The molecular mass of the toxin is approximately 10 000 according to sedimentation equilibrium sedimentation, Sodium dodecyl sulphate (SDS) gradient gel electrophoresis and calculations from the amino acid composition. Non-competitive proteinase inhibitory activity was found to be associated with the toxin. Histopathological lesions, observed in guinea-pigs inoculated with crude egg extracts or the purified toxin, included the following : focal areas of necrosis in the liver, with mineralization and oedema of the mucosa of the urinary bladder, and vacuolation of the lining epithelium. The genesis of the lesions in the various organs appears to be vascular.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Evidence for cryptosporidial infection as a cause of prolapse of the phallus and cloaca in ostrich chicks (Struthio camelus)

Cloacas of male ostrich chicks that had suffered prolapse of the phallus and cloaca were compared with cloacas of normal ostrich chicks of both sexes from the same area. Heavy infection of the cloacal and bursal tissue with Cryptosporidium sp. was present in all the cases of prolapse, while no cryptosporidia were observed in the normal chicks. Histopathological lesions as described in cryptosporidial infection in other species were present in the infected cloacas. These included loss of the microvillous border and epithelial hyperplasia, and degeneration, which was indicated ultrastructurally by vacuolation of the apical cytoplasm, swelling of organelles, and nuclear changes. It is suggested that these lesions, in combination with the anatomy of the male ostrich cloaca, may be responsible for prolapse of the phallus and cloaca.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201

Redescription de Setaria graberi Shoho in Troncy, Graber & Thal, 1976 (Nematoda: Filarioidea) base´e sur des spe´cimens de Redunca arundinum (Bovidae) en Afrique du Sud

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 lm apart in females and 71–93 lm in males, carry two wellseparated 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.La filaire Onchocercidae Setaria graberi Shoho in Troncy, Graber & Thal, 1976 est rede´crite a` partir de spe´cimens de la cavite´ abdominale du Grand Cobe des roseaux, Redunca arundinum (Boddaert), en Afrique du Sud, en incluant des illustrations et des images en microscopie e´lectronique a` balayage des aspects morphologiques importants. Des donne´es morphome´triques sont fournies pour la premie`re fois pour cette espe`ce. Setaria graberi est caracte´rise´e par la possession de deirides bifides, et par des femelles ayant une queue distinctement bulbeuse. La couronne pe´ribuccale le´ge`rement e´leve´e forme une unite´ en forme de cloche avec les e´le´vations ce´phaliques en vue apicale ; les e´le´vations dorsales et ventrales, se´pare´es par 73–115 lm chez la femelle et 71–93 lm chez le maˆle, portent chacune deux extre´mite´s bien se´pare´es. En vue dorso-ventrale, les e´le´vations ce´phaliques apparaissent plus ou moins rectangulaires avec un apex le´ge`rement entaille´ et sont e´troites par rapport a` l’e´paisseur de l’extre´mite´ ante´rieure. Elles sont triangulaires en vue late´rale. Quatre papilles ce´phaliques et quatre papilles labiales externes sont arrange´es en des rectangles allonge´s. L’espe`ce est distingue´e des autres espe`ces de Setaria Viborg, 1795 qui posse`de des deirides bifides ou se trouvent chez des hoˆtes membres du meˆme genre. La pre´sence de S. graberi chez R. arundinum en Afrique du Sud repre´sente un nouvel hoˆ te et une nouvelle mention ge´ographique.http://www.parasite-journal.org/am2013ab201

Nuttalliella namaqua (Ixodoidea: Nuttalliellidae) : first description of the male, immature stages and re-description of the female

Nuttalliella namaqua is the only species of the enigmatic third tick family. Females possess features of hard and soft ticks and have been designated as the ‘‘missing link’’ between the main tick families. Its position at the base of the tick tree suggests that some of the features unique to hard and soft ticks were present in the ancestral tick lineage. Larvae, nymphae and males have not been described to date and questions regarding their biological affinities to the main tick families remain unclear. The current study addressed these questions via the description of larvae, nymphae and males and resolved issues pertaining to female morphology. Field collected as well as laboratory-engorged females laid eggs and viable larvae subsequently hatched. The larvae possess morphological structures not present in subsequent stages: namely, a sclerotized scutum, pores on the dorsal surface of legs and a dentate anal plate. The last two characters are not present in ixodids and argasids. N. namaqua larvae and nymphae show a similar morphology to females: a unique hypostomal structure i.e., bluntly rounded apically in nymphae and females and ball-like in the larvae. A re-description of some structures in female N. namaqua has resolved differences in the original descriptions, namely that N. namaqua have 4 palpal segments as found in ixodids and argasids and posthypostomal setae. The male was discovered for the first time and described. Characteristic male features include: a pseudoscutum over most of the dorsum, an outgrowth on the chelicerae forming a unique rod-like structure similar to a spematodactyl in mites and medial extension of palpal segment 2 forming a large ventral crib for segment 4. All life stages possess some features found in hard and soft ticks and its status as the ‘‘missing link’’ between the tick families remains.The Joy Liebenberg Trust (21/19/JT02) allocated to BM, a South African National Research Foundation grant allocated to AL (NRF-Spain).http://www.plosone.orgab201

Lumpy skin disease of cattle : an emerging problem in the Sultanate of Oman

Lumpy skin disease (LSD) is a highly infectious disease of cattle caused by a virus belonging to the Capripoxvirus genus of the family Poxviridae. The purpose of this study is to place on record the first confirmation of LSD in the Sultanate. The disease was diagnosed and confirmed using polymerase chain reaction, histopathology, transmission electron microscopy and serum neutralization testing. The epizootic occurred in 2009 involving a large number of animals and covering a wide area including Nezwa, Alqabel, Sohar, Saham and Burimi. Morbidity and mortality rates of 29.7 and 26.3 %, and 13.6 and 15.4 % were observed at Nezwa and Sohar, respectively. The clinical signs were much more severe in Holstein–Friesian cattle compared to indigenous breeds and were characterized by multiple skin nodules covering the neck, back, perineum, tail, limbs and genital organs. Affected animals also exhibited lameness, emaciation and cessation of milk production. Oedema of limbs and brisket, and superficial lymph node enlargement were highly prominent. It is not known from where the virus originated, or how it spread to the Sultanate. The disease has become endemic in the country and is liable to extend to other Gulf Cooperation Council Countries and cause a pandemic. It is of major concern to the Omani dairy industry. Due to the widespread presence of screw worm, serious economic losses can follow outbreaks.South African ARChttp://link.springer.com/journal/11250hb201