Iranian Journal of Veterinary Research
Volume:24 Issue: 4, Autumn 2023

Bovine leukemia virus (BLV) is a member of the Retroviridae family and belongs to the Deltaretrovirus genus. It has a close relationship with human T-cell leukemia virus type I. BLV is responsible for causing enzootic bovine leukosis (EBL), a contagious disease that affects the bovine lymphatic system. This virus poses challenges for the global cattle industry, as it impacts cattle populations all over the world. Despite being widespread and impactful, BLV often goes unnoticed, with many researchers unaware of its presence and the potential consequences it carries. BLV demonstrates varying levels of pathogenicity. The majority of cattle (around 70%) become seropositive asymptomatic carriers, displaying no noticeable clinical symptoms. However, a smaller proportion of infected animals experience persistent lymphocytosis, characterized by an elevated number of lymphocytes in the bloodstream. If not monitored and managed, a subset of these persistently infected cattle may advance to lymphosarcoma. This condition typically presents as tumors in different lymphoid tissues, impacting various organs and overall health and productivity. Furthermore, recent research has highlighted the potential association between the occurrence of breast and lung cancer in humans and the presence of BLV. This review will delve into the recent discoveries concerning BLV, specifically exploring its epidemiology, the economic impact it has on the global cattle industry, its implications for human medicine, and the association between different alleles of the major histocompatibility complex (MHC) and susceptibility or resistance to BLV.

In recent years, the hazardous use of antibiotic growth promotors in the poultry industry has led to the development of drug resistance and violative tissue residues. Therefore, the European Union Regulation banned application of these growth promotors, and the international authorities have searched for other natural and safe feed additive sources as substitutes for antibiotics. Chitosan has been used as a feed-additive alternative in veterinary medicine practices worldwide. Chitosan and chitosan-based nanoparticles have been extensively investigated in the poultry production system and have proved several positive impacts. The overall performance parameters of broilers and layers have been improved following dietary treatments with chitosan. Besides, chitosan showed antimicrobial activity against many bacterial, fungal, viral, and parasitic diseases as well as boosting of the immune response. Modulation of the antioxidant activity and modification of some blood parameters have also been detected owing to dietary chitosan supplementations. Moreover, chitosan nanoparticles have been now applied as a vaccine delivery vehicle and a mucosal adjuvant for many important poultry bacterial and viral diseases. Therefore, this review article sheds light on the effects of chitosan and its nanoparticle forms on the production traits of broilers and layers, their antimicrobial, immuno-regulatory, and antioxidant properties, as well as their effects on the blood constituents and vaccine production.

Sarcocystis species are coccidian protozoan zoonotic parasites of the phylum Apicomplexa. There is a large diversity of Sarcocystis species. Some of them are pathogenic and dangerous to humans, domestic, and wild animals. Cattle are common intermediate hosts. The infection of meat with different species of Sarcocystis can be serious for public health.

The current study aimed to determine the prevalence of sarcocystosis in slaughtered buffaloes in Tanta city abattoirs, Nile Delta, Egypt.

Morphological and histological examinations and a molecular study were undertaken. A total of 517 locally bred buffaloes were slaughtered in Tanta city, Egypt. Each buffalo carcass was visually inspected for the presence of Sarcocystis macrocysts. Fifty tissue samples containing suspected cysts were examined by using different techniques including histology, transmission electron microscope (TEM), and PCR.

By visual inspection, the overall prevalence of suspected sarcocystosis was 26.5%. The highest infection rate was detected visually from the esophagus followed by skeletal muscles and diaphragm whereas the least was recorded in the tongue. Histological and TEM examination showed that the cysts were packed with bradyzoites separated by multiple septa. 100% of the sarcocysts diagnosed visually in the esophagus and muscles were confirmed by PCR, compared to only 25% of those detected in the tongue.

These results highlight the high prevalence of sarcocystosis among buffaloes in Egypt, possibly due to widespread environmental contamination by Sarcocystis oocysts. The use of molecular methods should be encouraged to confirm the identity of the suspected cysts.

Mycobacterium avium complex (MAC) is connected to human immunosuppressive diseases, including HIV-AIDS, and may pose a zoonotic threat. MAC causes lymphadenopathy in children, respiratory infection in adults, and generalized infection in immunocompromised individuals. Infection with nontuberculous Mycobacteria (NTM) in humans is now primarily brought on by MAC. Recently, MAC members have emerged as pathogenic organisms for animals and humans. While dogs are generally resistant to mycobacterial infections, there have been some cases of infection that result in systemic or disseminated diseases. The organisms can be transmitted to dogs through oral contact, and their faeces can be a possible source of infection for dog owners. It is important to note that this ailment is zoonotic, especially if infected pet dogs are in prolonged contact with their humans.

The study was planned to demonstrate the occurrence of MAC organisms and other Mycobacteria in dogs associated with lymphadenopathy cases with special emphasis on lymphadenitis.

A total of 123 samples (100 lymph node aspirates, 15 lymph node tissues, and 8 blood samples) from 83 dogs suspected of lymphadenitis accompanied by gastroenteritis, chronic skin infections, immunosuppression, chronic pulmonary diseases, and other chronic undiagnosed diseases were studied. The samples were processed for cytological and microscopic examination by Ziehl-Neelsen staining. Following the decontamination procedure, the aspiration and lymph node tissue samples were inoculated into Middlebrook 7H11 media for up to 8 weeks. The aspirated material was also directly used for molecular detection by triplex-nested polymerase chain reaction (nPCR) assay.

A cytological study revealed pyogranulomatous inflammation of the lymph node tissue. Impression smears from lymph node tissues displayed the presence of acid-fast organisms. Out of 83 cases of dogs, 8 were found to be positive for Mycobacterium spp. Among those 8 positive cases, 3 were confirmed to belong to MAC, and 5 belonged to the Mycobacterium tuberculosis complex (MTB complex).

MAC and MTB are the underestimated bacteria that could be the causative agents of lymphadenitis in animals.

Macrorhabdus ornithogaster (MO) is an infectious yeast which can cause acute gastric disturbances in birds. It has a worldwide distribution with a broad host-range of bird species.

Molecular identification and phylogenetic analysis of MO based on the 18S rRNA gene in companion birds of Iran.

A total of 54 stool samples were taken from birds (10 species) suspected of being infected. The presence of MO in collected stool samples was investigated using direct wet mount microscopy. Specific primers were designed to identify the MO 18S rRNA gene by using PCR. PCR products were sequenced and phylogenetic analysis was performed to determine the molecular diversity.

The obtained results demonstrated that 44.44% and 59.26% of the samples were diagnosed positive based on the first and second specific primers, respectively. MO was detected in the feces of canary, goldfinch, budgerigar, toucan, and English budge. Phylogenetic analysis revealed that MO sequence data from canaries, finches, and goldfinches had homology with an MO isolated from a German zebra finch. Moreover, MOs from cockatiels, rosy faced love birds, and budgerigars had a high phylogenetic similarity with multiple references, including American budgerigar, Japanese cockatiel, European goldfinch, and German budgerigar.

MO exists in many species of Iranian birds, including goldfinches, budgerigars, toucans, and English budgies. As indicated by phylogenetic and polymorphism data analysis, the newly designed specific primers spanning a large portion of 18S rRNA gene of MO, provides additional tool to detect and study the molecular diversity of MO.

A patent dual-lumen dialysis catheter is one of the basic requirements for efficient extracorporeal (EC) therapy.

The objective of this study was to measure the resistance to blood flow offered by straight and curved-extension dual-lumen dialysis catheters used for continuous renal replacement therapy (CRRT).

Twenty dogs suffering from acute kidney injury (AKI) were subjected to CRRT. The dogs were allocated randomly to Group-I (curved extension catheter, n=12) or Group II (straight extension catheter, n=8), based on the type of dual-lumen catheter used in CRRT. The catheter outflow and inflow pressures were recorded at blood pump speeds of 50 ml/min and 99-100 ml/min. Data were tested for normality, and differences in mean inflow and outflow catheter resistances were evaluated for statistical significance using independent samples t-tests.

Straight extension catheters offered lower inflow resistance than curved extension catheters at both 50 ml/min (41.50 ± 5.84 mm Hg vs. 63.75 ± 6.88 mm Hg, P=0.03) and 99-100 ml/min (63.00 ± 8.11 mm Hg vs. 86.92 ± 7.02 mm Hg, P=0.04) blood flow rates. Straight extension catheters also offered lower outflow resistance than curved catheters at 99-100 ml/min blood flow rate (-94.12 ± 7.91 mm Hg vs. -128.25 ± 7.56 mm Hg, P=0.01; the negative signs only indicate the direction of blood flow).

These findings suggest that straight-extension dual-lumen dialysis catheters perform better than the curved model in extracorporeal renal replacement therapy by considering their lower resistance to blood flow.

During past few years, the Ind-2001 lineage of the Middle East-South Asia topotype (ME-SA) of the foot-and-mouth disease (FMD) virus has been implicated in FMD outbreaks in Pakistan.

This work conducts a comprehensive evolutionary analysis of the Ind-2001 and Pan Asia II lineages, with a specific emphasis on their geographical distribution, lineage classification, and sub-lineage distribution within the region. Furthermore, it aims to expand our understanding of the conserved region of the VP1 protein.

Total samples (n=50) were subjected to antigen detection ELISA and RT-PCR for serotype determination. Confirmed serotype-O isolates (n=17) underwent sequencing for lineage comparison, mutation impact assessment on the VP1 protein GH loop, 3D structure prediction, and further comparative analysis.

Isolates collected from 2017 to 2020 were identified as serotypes O/ME-SA/Pan Asia II ANT10 and O/ME-SA/Pak14. Notably, isolates collected from 2020 to 2022 belonged to a novel FMDV serotype O/ME-SA/Ind-2001e lineage. Phylogenetic analyses indicated that these strains were distinct from dominant contemporaneous strains which may challenge Pakistan’s FMD control measures. These isolates exhibited variance in the VP1 epitope, specifically in amino acid residues 135-155, known to influence neutralizing antibody generation.

Observed mutations suggest potential challenges to current vaccination efficacy against FMD. This emphasizes enhanced FMD surveillance and demonstrates that tracking the emergence of the O/ME-SA/Ind-2001e lineage is important for determining FMD control strategies in Asia.

Infectious bursal disease (IBD) caused substantial economic loss in central and western India during 2020 and 2021.

The study was conducted to characterize IBD virus (IBDV) from field outbreaks.

The study was conducted on 360 samples from 42 poultry flocks. The samples were subjected to histopathology and molecular detection, followed by phylogenetic typing of the partial VP2 gene.

The mortality ranged from 15.25 to 60.18%. The necropsy showed hemorrhages on thigh muscles, mottled spleen, swelling of kidneys and bursae with hemorrhages, and cheesy exudate. Histopathology revealed extensive necrosis and depletion of follicular lymphoid cells within the cortex and medulla, along with widespread hemorrhages, edema, and cystic cavities in the bursa. The field isolates showed cytopathic effects in the seventh passage. The cytopathic effects included swelling, rounding, granulation of cytoplasm around the nucleus, fragmentation of the infected cells, and detachment. The reverse transcription-polymerase chain reaction amplified 664 bp partial VP2 gene. The phylogenetic analysis identified 19 field isolates as very virulent IBDVs (vvIBDVs) and three as classical strains.

The results indicated that different vvIBDV strains are involved in disease outbreaks in central and western India.

Osteodystrophia fibrosa (ODF) is a metabolic disorder affecting the skeletal system, causing progressive loss of calcified bone mass and its replacement with fibrous tissue, which may be a sequel to primary or secondary hyperparathyroidism. This report intends to document the clinicopathological findings of ODF in a flock of young goats fed primarily on a wheat bran-rich diet.

Case description: 

In a flock of 50 stall-fed goats aged 1 to 2 years, seven were clinically presented with bilateral facial enlargement, leading to dyspnea and difficulty in prehension and mastication. Among the seven clinically affected goats, four died in 2 months.

Findings/treatment and outcome: 

The clinical examination revealed bilateral mandibular enlargement and limb deformities. On radiography, the maxilla and mandible had decreased radiopacity. Fine needle aspiration cytology (FNAC) from the affected bones showed occasional fibroblasts and individual osteoclasts clusters. On necropsy, the enlarged mandible revealed a meaty consistency. Undecalcified histological sections of the mandible showed severe osteopenia, multiple osteoclasts, Howship’s lacunae, and extensive fibroplasia. Dietary corrective measures led to the prevention of ODF in the rest of the flock.

Excessive wheat bran feeding in stallfed goats might have led to calcium and phosphorus imbalance, resulting in nutritional secondary hyperparathyroidism and subsequent skeletal deformities. FNAC of the affected bones, gross and histological findings provide a clinicopathological diagnosis of ODF.

The paper describes the first documentary evidence of intestinal histoplasmosis in Indian goats.

Case description:

 A goat flock in delta region of Tamil Nadu with a report of mortality of eight animals with the history of inappetence, constipation, tenesmus and hematochezia. Three goat carcasses were presented for necropsy.

Findings/treatment and outcome:

 Postmortem examination showed mesenteric lymphadenomegaly with greyish yellow viscous contents. Ileum contained scattered dark brownish tubular concretions inside the lumen. Colon and caecum had scattered firm serosal and mucosal nodules with caseous exudate. Lumen contained viscous haemorrhagic content. Mucosa of the colon showed numerous tiny ulcers. Urinary bladder serosa showed a focal firm nodule with caseous exudate and irregular firm mass. Microscopically, lung revealed oval inclusions with clear halo in pulmonary macrophages. Caecum and colon showed ulcers with necrotic core. Necrotic border showed multinucleated giant cells and oval bodies with clear halo. Mesenteric lymph node and urinary bladder revealed pyogranulomatous inflammation with aggregation of macrophages filled with numerous tiny inclusions. Periodic acid-Schiff and Grocott’s methanamine silver staining techniques and morphological features of the inclusion confirmed it as Histoplasma capsulatum. The case showed a resemblance with human colonic histoplasmosis.

This report documents the first incidence of intestinal histoplasmosis in goats. Interestingly, the intestinal form of histoplasmosis is considered to be common in humans and it showed similarity with human disease in goats based on the gross and microscopic lesions.

Extragonadal teratoma in the head and neck region is unusual in veterinary medicine. So far, only one case of oropharyngeal teratoma has been reported in a cat.

Case description:

 In this report, a 5-month-old kitten was brought to the clinic with the complaint of difficulty breathing, food intake, and oropharyngeal mass. In clinical examination, there was a large mass, protruding from the localization included left buccal mucosa, soft palate, and extending into the oropharynx but no cranial extension was observed in CT scans. The mass was completely resected. Macroscopically, the mass measured 4.5 × 6.5 cm2 and contained solid and cystic areas associated with soft and hard tissue components.

Findings/treatment and outcome:

 Histopathology revealed an extragonadal solid-cystic (grade 0) oropharyngeal mature teratoma containing structures from endoderm, mesoderm, and ectoderm. After an 8-month follow-up control period, no signs of recurrence were observed.

The case was deemed worthy of being presented with its clinical, radiological, and pathological findings, and complete resection was curative for mature teratoma.

Heterakidosis is one of the most prevalent parasitic diseases in birds, the caecae of a variety of wild and domestic birds are infected with these nematodes. In pheasants, nodular typhlitis is a lethal disease caused mainly by infection with Heterakis isolonche alone or in conjunction with Heterakis gallinarum. H. gallinarum has long been recognized to infect birds with low pathogenicity, with only a few fatal cases previously reported.

Case description: 

This paper describes a case of fatal nodular typhlitis due to H. gallinarum in a male and female pair of adult golden pheasants (Chrysolophus pictus) from a zoological garden in Uttar Pradesh, India.

Findings/treatment and outcome: 

The caecum had multiple serosal and mucosal nodules, the majority of which were found to contain various stages of parasites embedded in the center along with the free forms in the caecal contents. Histopathologically, these nodules were generally represented by granulomas centered on necrotic parasite debris, with the occasional reactive fibrous hyperplastic tissue reaction. Based on the morphology and nematode-specific internal transcribed spacer (ITS) ITS1-5.8 rRNA-ITS2 region-based PCR, the nematode was identified as H. gallinarum. The presence of H. gallinarum was further confirmed by sequencing the ITS region followed by phylogenetic analysis. According to the author’s best knowledge, this is the first instance of H. gallinarum being linked to nodular typhlitis in pheasants in India.

Our findings confirm that H. gallinarum, other than H. isolonche, can induce severe nodular typhlitis with a fatal outcome in pheasants.