RUMINANTS

AHL camelid autopsy diagnoses, 2006 to 2016

Janet L Shapiro

Between 2006 and 2016, 13 llamas and 126 alpacas, were submitted to the AHL-Guelph and AHL-Kemptville locations for postmortem examination.

Abortions: In 16 of the 17 abortion/stillbirth submissions,no infectious etiology was found. Three of the abortions were associated with umbilical cord torsion. A protozoal etiology was suspected in a mid-gestation abortion submission with nonsuppurative encephalitis, multifocal hepatic necrosis, mild placentitis, placental necrosis, and mineralization and from which no bacteria or viruses were isolated. Congenital cataracts have been reported in camelids, and we received 1 stillbirth with bilateral congenital cataracts from which no bacteria, viruses, Mycoplasma spp. or Chlamydia spp. were detected.

1-14-day-old camelids: In 7/23 neonatal crias, the most common problem was congenital defects, of which the most common was choanal atresia. Presenting signs were

dyspnea and mouth-breathing since birth. Other developmental anomalies in this group included unilateral renal agenesis, renal cysts, multiple congenital heart defects, including persistent truncus arteriosus and ventricular septal defect. One cria, paretic since birth, had kyphosis, scoliosis, and subluxation of 2 cervical vertebrae. Systemic bacterial infection was caused by E.coli in 5/6 cases, and was associated with omphalitis in 1 case. Intestinal cryptosporidiosis, associated with a history of severe diarrhea, was diagnosed in a 10-dayold cria. The cria also had severe acute renal tubular necrosis; gentamicin renal toxicosis was suspected. Lymphosarcoma involving liver, kidney, spleen, bone marrow, lung and lymph nodes was diagnosed in 2 14-day-old crias, for which the predominant presenting sign was diarrhea in one and fever in the other. Lymphosarcoma is one of the most commonly diagnosed neoplasms of llamas and alpacas. West Nile virus (WNV) was detected by PCR and immunohistochemistry in a 14-day-old cria with meningitis, but its clinical significance was unknown as the cria also had lesions consistent with a systemic bacterial infection in liver and lung.

15-day to 1-year-old camelids: The most common clinical signs in this group were neurologic, and diagnoses included idiopathic encephalitis, meningoencephalitis, meningomyeloencephalitis and meningitis, as well as vertebral osteomyelitis, paravertebral abscesses, and cervical spinal cord degeneration resulting from previous neck trauma. An arachnoid cyst, dysgenesis of the occipital condyles, and hydrocephalus with secondary cerebral and hippocampal atrophy was diagnosed in an 8-mo-old alpaca that had a 1 mo clinical course of blindness and staggering. Septicemia caused by Streptococcus equi subsp zooepidemicus was diagnosed in 2 cases. This is the etiological agent of “alpaca fever” and is one of the most important diseases of camelids in some regions in South America. Transmission is via ingestion from contaminated objects or direct contact with infected animals, and systemic disease is often associated with physiologic stressors. Additional diagnoses in this group were mesenteric torsion, emaciation secondary to impaction of stomach compartment 3, urolithiasis, severe coccidiosis, systemic bacterial infection, and dilated cardiomyopathy in an 8-mo-old alpaca that also had partial collapse of the trachea interpreted as a congenital defect.

>1-year-old camelids: Neurologic disease was the most common diagnosis in camelids >1 y-old. Lesions consistent with parasitic meningoencephalitis caused by “meningeal worm”, Parelaphostrongylus tenuis, were found in 7 alpaca cases. Some affected herds had multiple cases of parasitic meningoencephalitis in consecutive years. Also diagnosed were polioencephalomalacia (2 cases), WNV infection (3 cases), cerebrocortical or intervertebral disc abscesses (3 cases), intervertebral disc protrusion with compression of the spinal cord, and degenerative myelopathy associated with previous severe neck trauma. A nursing alpaca with a 5-day course of anorexia, incoordination, and abnormal mentation had disseminated parasitic myositis and mild nonsuppurative encephalitis with large intramuscular organisms resembling Sarcocystis sp., possibly S. aucheniae. The significance of the intramuscular parasite is not known; infection with many species of Sarcocystis, including S. aucheniae, is usually an incidental finding.

Digestive tract disease was the second most common diagnosis in this age group. Dental diseases, including excessive tooth wear, malocclusion, tooth root abscesses, complicated by maxillary or mandibular osteomyelitis and/or septicemia, were causes of anorexia, lethargy, or emaciation. Two alpacas were euthanized because of choke. Gastric ulceration involving stomach compartment 3 was a frequent diagnosis, occasionally as resulting in death from bacterial and/or mycotic invasion, or perforation with secondary septic peritonitis, as well as an incidental finding in animals dying from other causes or associated with the use of non-steroidal anti-inflammatory drugs. Multiple alpacas in one herd had gastritis attributed to grain overload. Vague non-localizing clinical signs were caused by gastric squamous cell carcinoma in a 13-y-old alpaca. Lethargy or colic were the clinical presentations

of mesenteric torsion in 2 cases, 1 complicated by jejunal rupture, and a case of diaphragmatic herniation of compartment 1. Mixed gastrointestinal parasitic infections were a cause of emaciation or weight loss resulting in euthanasia, and were also incidental findings in animals dying of other diseases. Intestinal parasites identified including Nematodirus sp., Trichuris sp., Capillaria sp., and Hemonchus sp., as well as Monezia sp., Eimeria sp., Eimeria punoensis, and E. macusaniensis.

Emaciation was the third most common disease diagnosis. In >50% of cases, there was no predisposing disease found, and a primary nutritional etiology was suspected. Emaciated animals were found dead in 6/15 cases, but others had a short clinical course of lethargy or weight loss for a few hours to a few days before dying or being euthanized.

Liver lesions interpreted as nonspecific toxic hepatopathy, in 1 case accompanied by lesions of hepatic encephalopathy, were found in 3 cases. Hepatic necrosis and lipidosis was associated elevated liver copper levels and clinical signs of staggering and weight loss in a 7-y-old alpaca. Hepatic lipidosis was often found in conjunction with other diseases, such as local of systemic bacterial infections, enteric parasites, and gastric ulceration. Hepatocellular carcinoma was diagnosed in a 4-y-old alpaca.

Sporadic diagnoses in this group included urolithiasis, skeletal myopathy, idiopathic myocardial fibrosis, and bacterial myocarditis complicated by hemopericardium and cardiac tamponade. Prevotella melaninogenica bacteria were cultured from an intervertebral disc abscess and from a case of severe cellulitis of the neck. This organism may be found in the oral cavity, and in our cases, may have caused abscesses as a result of systemic spread from dental disease or bite wound of a carnivore.

Overnight prepaid courier services offered by AHL is continuing with Purolator Express Return Labels!

AHL has traditionally offered a prepaid overnight courier service for Ontario clients through Purolator Courier.

The good news! This is NOT changing. The method that is used to do this however IS changing.

The prepaid collect AHL courier account number is being retired on June 30, 2016, and is being replaced by Purolator Express Return Labels. We will be using these return labels for all prepaid Purolator Courier packages that are destined for the AHL. Please email ahl.supplies@uoguelph.ca to order your Purolator Express Return Labels!

See our LabNote 46 for more details

Do you recognize this plant?

Margaret Stalker

Image of Yew plant

Yew (Taxus spp.):

Who is at risk? Horses, livestock, and humans.

What part is toxic? All parts of the plant are toxic, except for the fleshy red aril covering the seed.

Clinical signs? Sudden onset of trembling, incoordination, difficulty breathing, slow heart rate, sudden death.

Comments:

Yews are hardy evergreen shrubs used widely in landscaping.
They contain taxine alkaloids that interfere with heart function, and are exceptionally toxic plants.
Yew poisoning is the most commonly diagnosed plant toxicity at the AHL, typically causing sudden death in cattle and horses.
Yews should never be planted around animal enclosures, and prunings should be kept away from all livestock, as they remain toxic even when dry. See also:

http://www.omafra.gov.on.ca/english/livestock/horses/facts/07-055.htm