Stable recombinant alpaca antibodies for detection of Tulip virus X

For detection of the plant pathogenic Tulip virus X (TuVX), a panel of six recombinant antibodies was identified. To this end, a repertoire of variable domains from heavy-chain immunoglobulins (VHH) was cloned from an alpaca, which had been immunized with TuVX. Binding domains were selected by phage display and panning on immobilized TuVX particles. Recombinant VHH antibodies were tested for sensitivity in a sandwich ELISA, and were demonstrated to be readily able to distinguish TuVX-infected tulip leaf material from uninfected leafs. No cross-reactivity of the VHH antibodies to related flexiviridae was observed. Recombinant VHHs maintained their reactivity upon storage at −20°C for over a year. The effect of incubation at higher temperatures for prolonged time was studied. Two out of three VHH proteins retained activity after several weeks of storage at 37°C.     

Humoral Response to 2 Inactivated Bluetongue Virus Serotype‐8 Vaccines in South American Camelids

Background: Bluetongue virus serotype 8 (BTV‐8) has caused disease in domestic ruminants in several countries of northern Europe since 2006. In 2008 a mass‐vaccination program was launched in most affected countries using whole virus inactivated vaccines. Objective: To evaluate 2 inactivated vaccines (Bovilis BTV 8; BTVPUR AlSap8) for immunogenicity and safety against BTV‐8 in South American camelids (SAC) in a field trial. Animals: Forty‐two SAC (25 Alpacas, 17 Llamas) aged between 1 and 16 years. Methods: The animals were vaccinated twice at intervals of 21 days. They were observed clinically for adverse local, systemic, or both reactions throughout the trial. Blood samples collected on days 0, 14, 21, 43, and 156 after vaccination were tested for the presence of BTV‐8 virus by real time‐polymerase chain reaction and of specific antibodies by competitive ELISA and a serum neutralization test. Results: All vaccinated animals developed antibodies to BTV‐8 after the 2nd administration of the vaccine. No adverse effects were observed except for moderate local swellings at the injection site, which disappeared within 21 days. Slightly increased body temperatures were only observed in the first 2 days after vaccination. The BTV was not detected in any of the samples analyzed. Conclusions and Clinical Importance: The administration of the 2 inactivated commercial vaccines was safe and induced seroconversion against BTV‐8 in all vaccinated animals. The results of this study suggest that 2 doses injected 3 weeks apart is a suitable vaccination regimen for SAC.     

羊驼细胞色素C氧化酶VIc亚基基因序列的测定与分析

本研究通过克隆分析羊驼细胞色素c氧化酶VIc亚基基因的序列,对羊驼细胞色素c氧化酶的VIc亚基基因的结构和功能进行了初步探索。实验利用免疫印迹技术（Southern blotting）对已有羊驼皮肤cDNA文库进行筛选并测序,结果表明该基因大小为424bp,含一个完整的ORF,位于36～266bp,编码77个氨基酸。对该基因序列分析表明：该基因编码的蛋白质含有疏水性区域、一个跨膜区并具有信号肽。同源性分析表明,核苷酸序列同源性为76％～100％。     

Internal structure and pigment granules in colored alpaca fibers

Alpaca fibers have some distinct properties such as softness and warmth, which have not been fully understood in combination with the fiber internal structures. In the present investigation, the internal structures of alpaca fibers have been closely examined under the scanning electron microscope (SEM), especially in the longitudinal direction. The results showed that numerous pigment granules reside loosely inside pockets in brown and dark-brown alpaca fibers. These pigment granules were mainly distributed inside the cortical cells, the medullation regions as well as underneath the cuticles. Their size in the brown alpaca fibers was smaller and more uniformly round than in the dark-brown fibers. These granules in colored alpaca fibers loosen the bundle of cortical cells, providing many crannies in the fibers which may contribute to the superior flexibility, warmth and softness of the fibers. Moreover, there are no heavy metal elements found in the granules. The mordant hydrogen peroxide bleaching employed could eliminate the pigment granules and create many nano-volumes for further dyeing of fibers into more attractive colors.     

羊驼人工采精技术的研究与精液特性

(山西农业大学动物科技学院,山西太谷 030801)     

Cryptosporidiosis in two alpaca (Lama pacos) holdings in the South-West of England

Cryptosporidiosis was investigated on two alpaca (Lama pacos) holdings in the South-West of England. Diagnosis was initially confirmed in a cria with diarrhoea from each holding. Cohort faeces samples were subsequently collected and examined for presence of Cryptosporidium oocysts by immunofluorescence microscopy. On the first holding, 30 samples (24 adults, 6 crias) were tested, and oocysts were detected in three of the cria samples but in none of the adults. On the second holding, 14 floor faeces samples representing apparently healthy crias and one faeces sample from a cria with diarrhoea were collected. Oocysts were detected in four of the "healthy" faeces samples and the sample of diarrhoeic faeces. All isolates were confirmed as Cryptosporidium parvum using polymerase chain reaction restriction fragment length polymorphism of the cryptosporidium oocyst wall protein (COWP) and ssu rRNA genes. Sequence analysis of a 741bp region of ssu rDNA was carried out on nine of these and revealed high sequence homology with previously reported C. parvum isolates. This investigation highlights the possibility of alpaca crias subclinically shedding oocysts, which has implications for epidemiology and transmission in animals as well as raising zoonotic concerns for human contacts. Gene sequencing of UK isolates from South American camelids is also described for the first time.     

Congenital caudal vertebral malformations in the alpaca (Lama pacos)

OBJECTIVE: To assess radiologically the caudal vertebrae of a male alpaca with an abnormal tail, and nine of his offspring. PROCEDURE: Right lateral and ventrodorsal radiographs were taken of the caudal vertebrae. RESULTS: The caudal vertebral abnormalities in these alpacas included vertebral subluxation, hemivertebrae, wedge hemivertebrae and block vertebrae. CONCLUSION: These malformations in offspring of one sire suggest a hereditary basis for congenital caudal vertebral malformations in the alpaca.     

A proof of concept study to assess the potential of PCR testing to detect natural Mycobacterium bovis infection in South American camelids

Background

Cases of Mycobacterium bovis infection South American camelids have been increasing in Great Britain. Current antemortem immunological tests have some limitations. Cases at post mortem examination frequently show extensive pathology. The feasibility of detecting Mycobacterium bovis DNA in clinical samples was investigated.

Findings

A sensitive extraction methodology was developed and used on nasal swabs and faeces taken post-mortem to assess the potential for a PCR test to detect Mycobacterium bovis in clinical samples. The gross pathology of the studied South American camelids was scored and a significantly greater proportion of South American camelids with more severe pathology were positive in both the nasal swab and faecal PCR tests. A combination of the nasal swab and faecal PCR tests detected 63.9% of all the South American camelids with pathology that were tested.

Conclusions

The results suggest that antemortem diagnosis of Mycobacterium bovis in South American camelids may be possible using a PCR test on clinical samples, however more work is required to determine sensitivity and specificity, and the practicalities of applying the test in the field.     

Myelodysplasia, hypophosphataemia, vitamin D and iron deficiency in an alpaca.

A pregnant 2-year-old alpaca was presented for evaluation of progressive weight loss, decreased appetite and lethargy that developed in winter. Haematologic and serum biochemical analyses revealed marked anaemia, leukopenia, severe hypophosphataemia and mild hypocalcaemia. Evaluation of bone marrow core biopsies and aspirates revealed an increased proportion of immature haematopoietic cells, without sufficient numbers of blast cells to be termed an acute myeloid leukaemia (AML). 1 The haematological and bone marrow findings were suggestive of myelodysplastic syndrome (MDS). The anaemia, leukopenia, lethargy and weight loss remained refractory to medical therapy and the alpaca was euthanased on humane grounds.