Natural aflatoxicosis in neonatal calves in a dairy herd – pathological diagnosis

Aflatoxins have been known as an important cause of animal disease for 30 years. The toxins occur naturally on animal feeds either in the field or during storage when moisture content and temperatures are sufficiently high for mould growth. The present paper describes clinical signs besides of gross and histopathological features of aflatoxicosis in 2 to 5-day-old dairy calves which were infected naturally in February 2017. According to the history and clinical examinations, clinical signs included anorexia, ataxia, reluctance to move, convulsion and neonatal mortality in 2 to 5-day-old calves in this herd. Also, black mould as Aspergillus niger was observed in storage animal feeds especially in rouphage and silage. At necropsy, there was sanguineous ascites with multifocal haemorrhages under serosal and mucosal surfaces of gastrointestinal tract, mesenteric lymph nodes, kidneys, and meninges. The liver and spleen were slightly enlarged and hyperaemic. Intramural oedema and haemorrhage were seen in the wall of gall bladder. Histopathological examinations revealed haemorrhagic enteritis, abomasitis and nephritis. There were multifocal large extramedullary haematopoiesis especially with accumulation of megakaryocytes in the liver and spleen. Moreover, the liver showed mild fatty changes in hepatocytes, centriacinar fibrosis with bile ductules proliferation. In the brain, there were perivascular and perineuronal oedema, and perivascular haemorrhage. According to these results, it seems that calves in this herd suffered from hepatoencephalopathy due to simultaneous acute and subacute aflatoxicosis in which aflatoxins originally produced in animal feeds and transferred during pregnancy and also postnatally via milk, were the cause of neonatal mortality in the herd.

Identification of p53 gene alterations in canine mammary tumours using polymerase chain reaction and direct sequence analysis

Mammary tumours are mentioned as the most common tumours in female dogs and approximately half of them are detected malignant. p53 gene mutations are demonstrated to be the most common genetic alteration in canine mammary tumours. The present study was conducted to evaluate exon-1 of p53 gene mutations in tissue samples of canine mammary tumours by PCR and direct sequence analysis. After histopathological confirmation of the tissue sections by haematoxylin and eosin staining (10/26), deparaffinised samples were used for DNA extraction by silica gel method. Subsequently, p53 exon 1 was amplified through PCR assay using specific oligo nucleotide primers designed according to the canine DNA sequence available online. Microscopically, 10 out of 26 suspected tissue samples were recognised as malignant mammary gland tumours with various grades of malignancy. Surprisingly, one insertion of mutation was found in exon 1 of all examined samples corresponding to a sequence comprising 27 amino acids, between amino acids 30 to 57 in the p53 protein. Taken together, it seems that alteration of exon 1 p53 gene may lead to malignancy beha­viour, poor prognosis and short survival time in dogs with mammary carcinomas.

Unusual ocular Hodgkinʼs-like lymphoma in a dog

Hodgkin’s disease is a malignant lymphoproliferative disease with various gross morphology. The present paper reports gross and microscopic features of Hodgkinʼs-like lymphoma in a dog. An eight years-old dog was presented to our hospital due to complete blindness associated with the presence of proliferative tissue on the globe surface. The tissue biopsy sample was soft and frigid with high bleeding tendency and was processed for histopathological evaluation. Sections of 5 μm in thickness were stained with haematoxylin-eosin and melan-A and S-100 by immunohistochemistry (IHC) for differential diagnosis with ocular melanoma. Histologically, regarding the negative Melan-A and S100 IHC findings, and particular histological features, a mixed cellularity type of Hodgkin’s disease which included a large number of lymphocytes with different size and shape together with single necrosis was diagnosed. Additionally, Reed-Sternberg cells which had a deeply lobulated nucleus were demonstrated.

Incidence and Genetic Characterization of Gongylonema pulchrum in Cattle Slaughtered in Mazandaran Province, Northern Iran

BACKGROUND

The gullet worm, Gongylonema pulchrum Molin, 1857, is a thread-like spirurid nematode found in a variety of mammals worldwide. Its incidences in Iranian cattle of different breed or age have not been reported. The aims of the present study are to disclose the infection status of G. pulchrum in cattle slaughtered in northern region of Iran.

METHODS

Full-length esophagi of cattle of 97 native dairy breed and 41 Holstein-Friesian breed were collected at four local abattoirs in Mazandaran Province, northern Iran, from March 2006 to August 2007, and were examined parasitologically. Eight overlapping segments of the small- and large-subunits of rDNA were amplified by PCR, and the obtained nucleotide sequences were characterized.

RESULTS

The incidences of G. pulchrum in female and male native dairy breed were 38.9% and 24.0%, respectively, whereas those in female and male Holstein-Friesian breed were 4.2% and 0%, respectively. The first internal transcribed spacer (ITS1) region of G. pulchrum rDNA showed an intra-individual variation in the sequence and length, and the variation was ascribed to some unstable repeats of "A" or "CA".

CONCLUSION

Distinct incidences of G. pulchrum infection in native dairy breed and Holstein-Friesian breed might be ascribed to different animal husbandry manners for each breed in Iran; the former breed grazes freely in the pasture, but the latter breed is usually held in a pen. The rDNA sequence of Iranian G. pulchrum, obtained for the first time by us, might facilitate a reliable species identification of the parasite with a wide spectrum of morphological variations.