A re-description of Physocephalus dromedarii stat. nov. (Nematoda: Spirocercidae), an abomasal nematode of dromedaries (Camelus dromedarius).

Physocephalus dromedarii stat. nov. was found in the abomasum of two adult female dromedaries originating from a farm in Dubai. Previously, this nematode has been misidentified as a subspecies of Ph. sexalatus but morphological differences are striking enough for it to be upgraded to a species. Physocephalus dromedarii is larger than Ph. sexalatus and has longer spicules. There are 20-22 oblique crests at the ventral surface between the caudal alae of the male compared to 7-8 in the case of Ph. sexalatus. The most significant differences are the presence of two pairs of papillae between cloaca and postcloacal plate of the male and the existence of a swelling in the second half of the female body formed by loops of both uterine horns.

Tuberculosis in camelids: a review.

Tuberculosis is a chronic, contagious, granulomatous disease caused by mycobacterial species belonging to the Mycobacterium tuberculosis complex. Camelids were not considered highly susceptible to tuberculosis, but in recent years increased numbers of cases have been experienced in some countries. In most of the cases, transmission probably occurs through contact with infected cattle or wildlife. None of the ante-mortem tests currently available can consistently provide accurate diagnosis of the infection in live camelids. Recently developed serological assays have the potential for rapid and accurate diagnosis of tuberculosis but still need to be validated.

Foot and mouth disease and similar virus infections in camelids: a review.

Foot and mouth disease (FMD) remains the most important animal disease. The FMD virus is highly contagious and occurs almost exclusively among cloven-hoofed animals such as cattle, sheep, goats, Bactrian camels and swine. Old World camels (OWCs) and New World camels (NWCs) inhabit FMD-endemic countries in South America, North and East Africa, and the Middle and Far East. Results of experimental infection of OWCs with the virus, and several clinical observations from the field over a century, confirm that the two closely related camel species of Bactrian and dromedary camels possess noticeably different susceptibilities to FMD. It is now certain that Bactrian camels can contract the disease. In contrast, dromedaries are not susceptible to FMD and do not transmit infection, even when in close contact with susceptible animals. The susceptibility of NWCs to the FMD virus has been demonstrated in the field and in experimental infection trials. However, these animals are not very susceptible and do not represent a serious risk in transmitting FMD to susceptible animal species.

Peste des petits ruminants in Arabian wildlife.

Recurrence of peste des petits ruminants (PPR) was diagnosed in the United Arabian Emirates in several wild ruminants confirmed by morphological, immunohistochemical, serological and molecular findings. Phylogenetic analysis revealed that the virus strain belongs to lineage IV, which is different to some previously isolated PPR strains from the Arabian Peninsula. This study shows that wild ruminants may play an important epidemiological role as virus source for domestic small ruminants.

Camelid immunoglobulins and nanobody technology.

It is well established that all camelids have unique antibodies circulating in their blood. Unlike antibodies from other species, these special antibodies are devoid of light chains and are composed of a heavy-chain homodimer. These so-called heavy-chain antibodies (HCAbs) are expressed after a V-D-J rearrangement and require dedicated constant gamma-genes. An immune response is raised in these so-called heavy-chain antibodies following classical immunization protocols. These HCAbs are easily purified from serum, and the antigen-binding fragment interacts with parts of the target that are less antigenic to conventional antibodies. Since the antigen-binding site of the dromedary HCAb is comprised in one single domain, referred to as variable domain of heavy chain of HCAb (VHH) or nanobody (Nb), we designed a strategy to clone the Nb repertoire of an immunized dromedary and to select the Nbs with specificity for our target antigens. The monoclonal Nbs are well produced in bacteria, are very stable and highly soluble, and bind their cognate antigen with high affinity and specificity. We have successfully developed recombinant Nbs for research purposes, as probe in biosensors, to diagnose infections, and to treat diseases like cancer or trypanosomosis.

Outbreak of microsporidiosis caused by Enterocytozoon bieneusi in falcons.

Four falcons from a private collection of 137 falcons in Abu Dhabi (UAE) died suddenly in summer 2005. In order to screen for a possible disease among the remaining falcons in the aviary, all other birds were caught, examined and treated if necessary. Most of the falcons suffered from massive lice infestation and 74 falcons additionally from a heavy Caryospora sp. burden. Endoscopy revealed yellowish plaques on intestines, livers or kidneys in 70 birds (51.1% morbidity). Proliferative serositis was seen in 17 out of 24 necropsied birds with plaques on intestines, livers or kidneys, which did not resemble any known disease in falcons. However, apart from 20 falcons, which died within a 6-week period after the initial examinations due to advanced disease stages, all other falcons responded well to the treatment with dimetridazole (Emtryl), indicating protozoal disease. Immunohistochemistry confirmed the presence of microsporidial antigen. The final diagnosis of Enterocytozoon (E.) bieneusi genotype D was confirmed with materials from 6 birds by PCR and sequencing. To our knowledge this is the first report of microsporidiosis caused by E. bieneusi in raptors in general and in falcons in particular. However, it is still unclear for how long E. bieneusi was present in the falcon flock, and which role it played in the development of the disease. Predisposing factors such as high temperature and overcrowding in the aviary induced immune suppression causing massive lice infestation as well as coccidiosis, thus paving the way for invasion with microsporidial spores.

Tuberculosis outbreak in a dromedary racing herd and rapid serological detection of infected camels.

A recent outbreak of tuberculosis (TB) in a dromedary racing herd of 58 animals involved 3 infected animals. Disease was confirmed at necropsy by finding gross lesions from which Mycobacterium bovis (antelope type) was isolated. Sera collected from the camels in this herd were used to evaluate two new serological methods, Multiantigen Print Immunoassay (MAPIA) and rapid test (RT) developed using the lateral-flow technology, in comparison with the intradermal tuberculin tests. Antibodies were found in all three infected dromedaries by both RT and MAPIA, but not in the remaining 55 animals in the herd. With the limited number of animals tested in this study, the serological assays showed the potential for convenient, rapid, and accurate diagnosis of TB in live camels.

[Glanders--a comprehensive review]. / Ein Ubersichtsreferat zur Rotzerkrankung.

Since 1990 the number of glanders outbreaks in race, military and pleasure horses in Asia and South America is steadily increasing. Glanders, which is eradicated in Western Europe, Australia and Northern America, is currently considered a re-emerging disease. Consequently, the disease may be introduced into glanders-free regions by subclinical carriers at any time. The causative agent of glanders, Burkholderia (B.) mallei, is highly contagious and leads to chronic disease in horses whereas in donkeys and mules the disease is acute and often fatal. Occurrence of the disease leads to international trading restrictions and infected animals immediately have to be culled and safely disposed off. In humans B. mallei infection results in a severe clinical course, and is fatal without appropriate therapy. Its pathogenicity makes B. mallei a potential biological agent that may be used in bioterroristic attacks. Due to the eradication of glanders in the second half of the last century, veterinarians in western European countries are no longer familiar with its clinical presentation in solipeds. Having these facts in mind, this review describes the epidemiology, clinical signs, pathology and the current eradication strategy of this interesting zoonosis. Pictures of imported endurance horses infected with glanders taken during an eradication campaign in Dubai, United Arab Emirates, in 2004 illustrate most typical clinical findings.

Ventricular septal defect in a houbara bustard (Chlamydotis undulata macqueenii).

A ventricular septal defect was found in a juvenile captive-bred houbara bustard (Chlamydotis undulata) that died suddenly. The case history indicated that the bird had a retarded growth and maturation rate. Gross pathology demonstrated massive internal hemorrhage, an enlarged heart with an interventricular septal defect, one shrunken liver lobe, and hypoplastic kidneys. Histologically, the liver was characterized by fatty degeneration, and there was hydropic degeneration of the cardiac muscle fibers. We suggest that the occurrence of this defect led to cardiac insufficiency, which resulted in sudden death caused by hemorrhage from the liver.

Pathological studies on camelpox lesions of the respiratory system in the United Arab Emirates (UAE).

Three dromedary camels (Camelus dromedarius), which died from generalized camelpox with lesions in the respiratory system, were investigated. Histopathological lesions in the lung consisted of small, sometimes confluent foci of proliferated bronchial epithelium, necrosis and fibrosis. Orthopoxvirus cameli was demonstrated in all three cases by transmission electron microscopy and the virus was isolated from the lung and trachea on Dubca cells. It was proved by restriction enzyme analysis of the viral DNA that the isolates were identical. Immunohistochemical examination showed numerous poxvirus antigen-positive cells in the bronchial epithelia. Immunolabelled material was found in bronchial epithelial cells with hydropic degeneration and in infiltrating macrophages.

Derivation of mean impedance curves as a basis for mechanical models of the human hand-arm system.

he use of mechanical models of the human hand-arm system in test stands can substitute man in several activities with exposition to vibration. An example is prototype testing of percussion drills. Modelling should be based on ascertained mean impedance curves of the hand-arm system. The method chosen was deriving curves for the three directions by using DIN and ISO standards (such as DIN 45677) as well as comprehensive literature and results of own measurements. At present it can be stated that: Literature is scarce especially with regard to the test conditions. Thus the causes of--sometimes largely--varying test results are difficult or impossible to be traced. There is conformity with the standards in principle. However, deviations exist for the frequency range determining the aw-value so that the application of mean standard curves for modelling the hand-arm system can lead to mistakes compared to test persons. Literature clearly shows an influence of hand grip force on the impedance curves. Standardisation seems not to consider this influence sufficiently. Mechanical models should take it into account. For feed force, there is no evidence for such a clear influence on the impedance curves.

Disseminated Rhodococcus equi infection in dromedary camels (Camelus dromedarius).

Rhodococcus (R). equi, a recognized pathogen in horses, is emerging as a human opportunistic pathogen, especially in immunocompromized people. It affects also New World camelids, but there are no reports of R. equi infection in Old World camelids yet. Four cases of disseminated R. equi infection in adult breeding dromedaries occurred at one camel farm near Dubai within 16 months of each other. At necropsy the lungs were diffusely consolidated with large caseous areas. Histology revealed severe suppurative to necrotising pneumonia with multiple encapsulated abscesses. Immunohistochemistry enabled the detection of 15- to 17-kDa antigens (VapA) of R. equi in the lung sections. High numbers of R. equi were isolated from the lung lesions as well as from liver, spleen and mediastinal lymph nodes, indicative of septicaemia. The isolated strains were PCR-positive for the specific virulence plasmid (VapA-Gen) of R. equi, indicating virulent strains and containing an 85-kb type I plasmid. This is the first report of disseminated R. equi infection in Old World camelids. Since adult camels in general do not suffer from bacterial caused pneumonia (except tuberculosis), this is a new emerging disease for camels.

Is there a two-humped stage in the embryonic development of the dromedary?

It has been postulated that the one-humped (Arabian) dromedary and the two-humped (Bactrian) camel originated from a single ancestor. Consequently, the dromedary was considered a breed of the two-humped camel, based on an anatomical study by Lombardini L, 1879: Ann. Del. Universita Toscane, 259, 147, who described a reduced second hump like structure in foetal and adult dromedaries. To resolve this lingering issue, we analysed dromedary foetuses and calves. In contrast to the situation in two-humped camels, we never observed any rudimentary second hump in the dromedary foetuses or calves.

Differences in the susceptibility of dromedary and Bactrian camels to foot-and-mouth disease virus.

In this study, two sheep, eight dromedary camels and two Bactrian camels were inoculated with foot-and-mouth disease virus (FMDV) type A SAU 22/92. Five naive dromedary camels and four sheep were kept in direct or indirect contact with the inoculated camels. The inoculated sheep, which served as positive controls, displayed typical moderate clinical signs of FMD and developed viraemia and high antibody titres. The presence of the virus was also detected in probang and mouth-swab samples for several days after inoculation. In contrast, the inoculated dromedary camels were not susceptible to FMDV type A infection. None of them showed clinical signs of FMD or developed viraemia or specific anti-FMDV antibodies despite the high dose of virus inoculated. All the contact sheep and contact dromedaries that were kept together with the inoculated camels remained virus-negative and did not seroconvert when tested up to 28 days post-inoculation (p.i.). In comparison with the non-susceptible dromedaries, the two inoculated Bactrian camels showed moderate to severe clinical signs of FMD; however, the clinical signs of FMD appeared rather late, between 8 and 14 days p.i., compared to the inoculated sheep. Characteristic FMD lesions in the Bactrian camels, accompanied with severe lameness, were only observed on the hind feet. The presence of the virus in the serum samples of both Bactrian camels was detected by real-time RT-PCR in one of the animals on days 3 and 7 p.i. and in the second animal from days 1 to 3 p.i. and subsequently again on day 21 p.i. The Bactrian camels developed high titres of antibodies to the inoculated FMDV which appeared at 7-10 days p.i. and lasted up to 130 days p.i. Only low and transient amounts of FMDV were detected in the mouth-swab and probang samples collected from both Bactrian camels.

Distribution patterns of the glucose transporters GLUT4 and GLUT1 in skeletal muscles of rats (Rattus norvegicus), pigs (Sus scrofa), cows (Bos taurus), adult goats, goat kids (Capra hircus), and camels (Camelus dromedarius).

Earlier studies demonstrated that forestomach herbivores are less insulin sensitive than monogastric omnivores. The present study was carried out to determine if different distribution patterns of the glucose transporters GLUT1 and GLUT4 may contribute to these different insulin sensitivities. Western blotting was used to measure GLUT1 and GLUT4 protein contents in oxidative (masseter, diaphragm) and glycolytic (longissimus lumborum, semitendinosus) skeletal muscle membranes of monogastric omnivores (rats and pigs), and of forestomach herbivores (cows, adult goats, goat kids, and camels). Muscles were characterized biochemically. Comparing red and white muscles, the isocitrate dehydrogenase (ICDH) activity was 1.5-15-times higher in oxidative muscles of all species, whereas lactate dehydrogenase (LDH) activity was 1.4-4.4-times higher in glycolytic muscles except in adult goats. GLUT4 levels were 1.5-6.3-times higher in oxidative muscles. GLUT1 levels were 2.2-8.3-times higher in glycolytic muscles in forestomach herbivores but not in monogastric animals. We conclude that GLUT1 may be the predominant glucose transporter in glycolytic muscles of ruminating animals. The GLUT1 distribution patterns were identical in adult and pre-ruminant goats, indicating that GLUT1 expression among these muscles is determined genetically. The high blood glucose levels of camels cited in literature may be due to an "NIDDM-like" impaired GLUT4 activity in skeletal muscle.

Development and clinical evaluation of a PCR assay targeting the metalloprotease gene (mprA) of B. pseudomallei.

A PCR assay targeting the metalloprotease gene (mprA) of Burkholderia pseudomallei was developed for the specific detection of this organism in pure cultures and clinical samples. All other closely related organisms including B. mallei the causative agent of glanders, and B. thailandensis tested negative. Burkholderia pseudomallei DNA was successfully amplified from paraffin-embedded lung tissue of a camel with a generalized B. pseudomallei infection. The developed PCR assay can be used as a simple tool for the specific and sensitive detection of B. pseudomallei.

Camel tuberculosis--a case report.

An adult male dromedary bull was diagnosed with pulmonary tuberculosis (Tb). The dromedary was severely emaciated and died 2 months after the onset of the disease. It exhibited typical Tb lesions in both lungs and lung lymph nodes. A guinea pig inoculated with lung tissue from theTb camel died after 3 weeks from typical Tb. Mycobacteria were isolated from the dromedary's lung and lung lymph nodes and also from different organs of the guinea pig. The microorganism was identified as member of the antelope clade of the Mycobacterium tuberculosis complex.

Production of a falcon herpesvirus vaccine.

Ten common kestrels (Falco tinnunculus) were used for this falcon herpes vaccine experiment. Four kestrels were subcutaneously given 1 ml of an attenuated falcon herpesvirus that had originally been isolated from the liver of an American prairie falcon (Falco mexicanus). This virus was then passaged 100 times on chicken embryo fibroblast cells (CEF-cells). Another 4 kestrels were given subcutaneously an inactivated falcon herpesvirus vaccine derived from the same American field strain. This vaccine was concentrated, inactivated by heat and betapropiolactone and emulsified in complete Freund's adjuvans. Two further kestrels served as controls and were not vaccinated. Twenty-one days after vaccination, all 10 kestrels were challenged with passage 3 of the American falcon herpesvirus. The 2 control kestrels died 6 days after challenge and 3 of those given the inactivated herpes vaccine died 9 days after challenge, with typical lesions of herpesvirus inclusion body hepatitis. Before the vaccination experiment, all 10 kestrels were free of serum neutralising antibodies to the falcon herpesvirus. Twenty-one days after vaccination, all 4 kestrels vaccinated with the attenuated vaccine, and one vaccinated with the killed vaccine, had seroconverted, having shown no symptoms to the challenge with a low passage virulent American herpesvirus strain. Following the challenge their antibody titres to falcon herpesvirus increased. No herpesvirus was isolated from any of the cloacal swabs taken during this experiment, indicating that there is no danger for any other birds from the attenuated herpesvirus vaccine. This experiment clearly shows that an attenuated falcon herpesvirus vaccine can protect kestrels from fatal inclusion body hepatitis.