Evaluation of a vaccine candidate isolated from Cryptosporidium parvum oocyst in mice

Research (Published online: 05-12-2022)

3. Evaluation of a vaccine candidate isolated from Cryptosporidium parvum oocyst in mice

Dina Aboelsoued, Hend H. A. M. Abdullah, Kadria N. Abdel Megeed, Soad E. Hassan, and Nagwa I. Toaleb

Veterinary World, 15(12): 2772-2784

ABSTRACT

Background and Aim: Cryptosporidiosis is a leading cause of diarrheal disease worldwide and is an animal and public health burden. This study aimed to evaluate the protective potential of affinity-purified Cryptosporidium parvum oocyst antigen as a vaccine candidate according to fecal oocyst shedding, humoral and cellular immune responses, histopathological changes, and the number of parasite developmental stages in ileal and hepatic tissues.

Materials and Methods: We isolated oocysts from naturally infected buffalo calves and identified them molecularly as C. parvum isolates (GenBank: ON730707 and ON730708) by targeting the Cryptosporidium oocyst wall protein gene. We propagated the C. parvum oocysts in mice. In addition, we prepared crude antigen from the isolated oocysts by purification using cyanogen bromide-activated Sepharose-4B affinity chromatography coupled with rabbit hyperimmune serum. Then, we divided 81 parasite-free mice into three groups: (1) non-vaccinated non-infected mice, (2) mice orally infected with 1 × 105 C. parvum oocysts on week 4 of the experiment, and (3) mice immunized twice with 40 μg/kg of the purified fraction at 2-week intervals. Then, we challenged the vaccinated group with C. parvum oocysts after 2 weeks, and the positive control group was infected at the same time.

Results: We observed a prolonged prepatent period and decreased oocyst shedding in the vaccinated infected mice compared with the non-vaccinated infected mice (t < 0.001). The vaccinated mice had significantly higher immunoglobulin G levels than those in the other two groups at all examined weeks. In addition, the production of cytokines interferon-gamma, interleukin (IL)-10, IL-12, and IL-15 was activated post-vaccination. After the challenge, all tested cytokines were significantly increased (p < 0.001) in the two infected groups compared with the non-vaccinated non-infected group, with the highest levels in the vaccinated infected group. Vaccinated infected mice exhibited significantly fewer pathological lesions in the ileum and liver than non-vaccinated infected mice, which showed prominent histopathological lesions. Endogenous developmental stages of C. parvum indicated that the ileum was more parasitized than the liver and that vaccination resulted in a lower number of oocysts in ileal and hepatic tissues (p < 0.05).

Conclusion: Our prepared affinity-purified vaccine candidate could be promising in protecting against cryptosporidiosis.

Keywords: affinity chromatography, Cryptosporidium parvum, cytokines, enzyme-linked immunosorbent assay, histopathology, polymerase chain reaction, vaccine.

Lumpy skin disease: A newly emerging disease in Southeast Asia

Review (Published online: 05-12-2022)

2. Lumpy skin disease: A newly emerging disease in Southeast Asia

Kanokwan Ratyotha, Suksanti Prakobwong, and Supawadee Piratae

Veterinary World, 15(12): 2764-2771

ABSTRACT

Lumpy skin disease (LSD) is caused by LSD virus (LSDV). This virus has been classified in the genus Capripoxvirus, family Poxviridae which generally affects large ruminants, especially cattle and domestic water buffalo. The first outbreak of LSD was found in 1929 in Zambia, then spreading throughout Africa and with an ongoing expanding distribution to Asia and Europe. In 2020, LSD was found from Southeast Asia in Vietnam and Myanmar before reaching Thailand and Laos in 2021. Therefore, LSD is a newly emerging disease that occurs in Southeast Asia and needs more research about pathology, transmission, diagnosis, distribution, prevention, and control. The results from this review show the nature of LSD, distribution, and epidemic maps which are helpful for further information on the control and prevention of LSD.

Keywords: Capripoxvirus, distribution, lumpy skin disease, newly emerging disease, Southeast Asia.

Sensitivity and specificity for African horse sickness antibodies detection using monovalent and polyvalent vaccine antigen-based dot blotting

Research (Published online: 05-12-2022)

1. Sensitivity and specificity for African horse sickness antibodies detection using monovalent and polyvalent vaccine antigen-based dot blotting

Machimaporn Taesuji, Khate Rattanamas, Usakorn Kulthonggate, Thanongsak Mamom, and Sakchai Ruenphet

Veterinary World, 15(12): 2760-2763

ABSTRACT

Background and Aim: The immune responses of animals infected with African horse sickness (AHS) virus are determined by enzyme-linked immunosorbent assay (ELISA), complement fixation, and virus neutralization test. During the outbreaks of AHS in Thailand, the immune response after vaccination has been monitored using commercial test kits such as blocking ELISA, which are expensive imported products unavailable commercially in Thailand. This study aimed to assess the sensitivity and specificity of anti-AHS virus antibodies using dot blotting based on monovalent and polyvalent strains of live attenuated AHS vaccine.

Materials and Methods: A total of 186 horse sera, namely, 93 AHS-unvaccinated samples and 93 AHS-vaccinated samples, were used in this study. All sera underwent antibodies detection using commercial blocking ELISA and in-house dot blotting based on monovalent and polyvalent strains of live attenuated AHS vaccine. The numbers of true positive, false positive, true negative, and false negative results in the dot blotting were compared with those in blocking ELISA and the sensitivity and specificity of dot blotting were assessed.

Results: For the monovalent antigen, there were 78, 19, 74, and 15 true positive, false positive, true negative, and false negative results, respectively, while for the polyvalent antigen, the corresponding numbers were 84, 34, 58, and 9. Meanwhile, the diagnostic sensitivity and specificity for monovalent antigen were 83.87% and 79.57%, respectively, but 90.32% and 62.37% for polyvalent antigen.

Conclusion: Dot blotting for AHS antibodies detection using vaccine antigen showed high sensitivity and rather a high specificity compared with the findings with the commercial ELISA test kit. In countries where commercial ELISA test kits are not available and when the size of a serum sample is small, dot blotting could become a good alternative test given its advantages, including its simplicity, rapidity, and convenience. To the best of our knowledge, these findings are the first report on the use of dot blotting for detecting AHS antibodies in horses. In conclusion, monovalent antigen-based dot blotting could be used as a reliable alternative serodiagnostic test for monitoring AHS humoral immune response, especially in vaccinated horses.

Keywords: African horse sickness, blocking enzyme-linked immunosorbent assay, dot blotting, sensitivity, specificity.

Sensitivity of RNA viral nucleic acid-based detection of avian influenza virus, Newcastle disease virus, and African horse sickness virus on flinders technology associates card using conventional reverse-transcription polymerase chain reaction

Research (Published online: 30-11-2022)

28. Sensitivity of RNA viral nucleic acid-based detection of avian influenza virus, Newcastle disease virus, and African horse sickness virus on flinders technology associates card using conventional reverse-transcription polymerase chain reaction

Khate Rattanamas, Machimaporn Taesuji, Usakorn Kulthonggate, Tippawan Jantafong, Thanongsak Mamom, and Sakchai Ruenphet

Veterinary World, 15(11): 2754-2759

ABSTRACT

Background and Aim: The flinders technology associates (FTA) card is a cotton-based cellulose membrane impregnated with a chaotropic agent that inactivates infectious microorganisms, lyses cellular material, and fixes DNA and/or RNA within the fiber matrix. However, little is known about the effectiveness of these cards for detecting RNA viruses in animals. This study aimed to evaluate the sensitivity of RNA virus detection using conventional reverse-transcription polymerase chain reaction (RT-PCR) on FTA cards.

Materials and Methods: A highly virulent Newcastle disease virus (NDV) and an avian influenza virus (AIV) with low pathogenicity were propagated using chicken embryonic eggs. Three days after inoculation, the allantoic fluid was harvested, stored at –80°C, and the stock virus was tested for virus titration. African horse sickness virus (AHSV) was obtained from a live attenuated vaccine that was dissolved and stored at –80°C. For sample preparation, each stock virus was 10-fold serially diluted and each dilution was inoculated onto an FTA card, followed by drying in a Class II safety cabinet. Both the stock virus and infected FTA card were genomically isolated using an extraction kit, FTA purification kit, and extraction kit with Tris-EDTA (TE) buffer. The target genome was then detected by one-step RT-PCR for NDV and AIV, and two-step RT-PCR for African horse sickness, including gel electrophoresis for the detection of specific nucleic acids.

Results: The detection limit of stock AIV was compared on FTA cards, using the FTA purification kit, and with TE buffer with an extraction kit. The corresponding results were 1.47, 1.17, and 2.18 log10 EID50, respectively, while for NDV the results were 4.13, 4.83, and 4.84 log10 ELD50. Finally, detection limit of stock AHSV and AHSV on the FTA card extracted using TE buffer with an extraction kit were 4.30 and 4.01 log10 plaque-forming units, respectively.

Conclusion: This study demonstrated that the detection limit or sensitivity of all tested RNA viruses on FTA cards did not differ when compared with those of the stock virus and in both methods for RNA isolation on FTA cards. These cards are suitable for collecting and transporting samples infected with RNA viruses, particularly AIV, NDV, and AHSV. Flinders technology associates cards also provide hazard-free samples, a reliable source of RNA for molecular characterization, and sufficient quantity for diagnostic applications based on nucleic acid-based detection.

Keywords: African horse sickness virus, avian influenza virus, flinders technology associates card, Newcastle disease virus, sensitivity.

Zoonotic diseases risk perception and infection prevention and control practices among poultry farmers in the Buea Health District, Cameroon: A one health perspective

Research (Published online: 30-11-2022)

27. Zoonotic diseases risk perception and infection prevention and control practices among poultry farmers in the Buea Health District, Cameroon: A one health perspective

Marie Ebob Agbortabot Bissong, Johnny Castro Nganjo Lyombe, Emmanuel Asongalem, Robert Bongji Ngamsha, and Nicholas Tendongfor

Veterinary World, 15(11): 2744-2753

ABSTRACT

Background and Aim: Livestock are associated with pathogenic microbes and farm workers play a significant role in the transmission of zoonotic diseases (ZDs). Lack of awareness of exposure risk among farmers may influence their farm practices thereby enhancing the spread of diseases on farms and to the community. This study was aimed at evaluating the knowledge, risk perception, and prevention and control practices of ZDs among poultry farmers to provide baseline data for establishing a "One Health" practical approach to reducing ZD transmission in poultry farms.

Materials and Methods: Using the exponential discriminative snowball technique, a community-based cross-sectional study involving poultry farmers was carried out in the Buea Health District from April to July 2021. Six feed-producing mills were used as focal points to identify and recruit farmers who also referred to other farmers. Questionnaires were used to collect data related to participants' knowledge, risk perception, and prevention and control practices of ZDs. Descriptive analyses were performed for all variables while the chi-square test and logistic regression analysis were used to determine associations at 95% confidence level.

Results: In all, 183 poultry farms and 207 workers were enrolled in the study. Despite being aware that animal diseases can be transmitted to humans, most participants showed poor knowledge (54.6%), low-risk perception (51.7%), and poor prevention/control practices (54.1%) on ZDs. The majority did not consider coming in contact with birds' body fluid (blood) or apparently healthy birds to be a risk of infection. More participants with small farms (<500 birds) had low-risk perception of ZDs than those with larger farms (>1000 birds) (p = 0.03). Furthermore, most participants reported practicing hand washing but they neither used protective devices such as gloves and face masks, and >50% would not invite veterinary professionals to their farms. There was a significant association between risk perception and knowledge (p = 0.007; CI = 1.257–4.200) as well as between risk perception and prevention/control practice (p = 0.002; CI = 1.451–4.867).

Conclusion: Poultry farm workers in Buea had poor knowledge and perception of ZD risk and this might have contributed to their poor prevention/control practices on the farms. Enhanced informal education of poultry farmers through training workshops and seminars will improve their knowledge and skills on ZD transmission risk and prevention.

Keywords: Cameroon, control practices, knowledge, poultry farmers, risk perception, Zoonotic diseases.

Association of natural resistance-associated macrophage protein 1 polymorphisms with Salmonella fecal shedding and hematological traits in pigs

Research (Published online: 29-11-2022)

26. Association of natural resistance-associated macrophage protein 1 polymorphisms with Salmonella fecal shedding and hematological traits in pigs

Nattariga Suwannawong, Uschara Thumarat, and Pitchayanipa Phongphanich

Veterinary World, 15(11): 2738-2743

ABSTRACT

Background and Aim: Natural resistance-associated macrophage protein 1 encoding gene (Nramp1) plays a role in immune response and disease resistance. This study aimed to investigate the polymorphisms of Nramp1 intron 6 concerning Salmonella shedding and hematological traits in pigs.

Materials and Methods: A total of 40 commercial pigs (three-way Large White x Landrace x Duroc cross) were genotyped using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and analyze the relationship between the polymorphisms of the Nramp1 gene and Salmonella fecal shedding and hematological parameters.

Results: Nramp1 was shown to be polymorphic in these pigs. The Nramp1 gene has two alleles (A and B) and two genotypes (AB and BB). The BB genotype had a higher frequency than the AB genotype. A significant relationship between the BB genotype and the number of Salmonella in feces compared to the AB genotype (p < 0.05) on 7 days post-inoculation (DPI) was revealed in the association analysis. The single-nucleotide polymorphism at intron 6 in the Nramp1 gene was linked to white and red blood cells 2 and 7 DPI (p < 0.05).

Conclusion: The Nramp1 gene was suggested by these findings to be potentially used as a molecular marker for the genetic selection of disease susceptibility in pig breeding.

Keywords: hematological trait, Nramp1, Salmonella shedding pig.

In vitro phytochemical analysis and antibacterial and antifungal efficacy assessment of ethanolic and aqueous extracts of Rumex nervosus leaves against selected bacteria and fungi

Research (Published online: 29-11-2022)

25. In vitro phytochemical analysis and antibacterial and antifungal efficacy assessment of ethanolic and aqueous extracts of Rumex nervosus leaves against selected bacteria and fungi

Maged A. Al-Garadi, Mohammed M. Qaid, Abdulmohsen H. Alqhtani, Anthony Pokoo-Aikins, and Saud I. Al-Mufarrej

Veterinary World, 15(11): 2725-2737

ABSTRACT

Background and Aim: Scientists are interested in identifying natural antibiotic substitutes that are effective against drug-resistant pathogenic microbes and spoilage fungi to counter pathogens and reduce the major public health problem of antibiotic residues in animal products. This study aimed to evaluate the antimicrobial activity of Rumex nervosus leaves (RNL) as a medicinal herb against four bacterial and two fungal strains using absolute ethanol, 50% ethanol, and aqueous extracts.

Materials and Methods: The antimicrobial activities of various RNL extracts against selected microbes were evaluated using the disk diffusion antibiotic susceptibility test, minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), minimum fungicidal concentrations, and the poisoned food technique.

Results: The absolute ethanol RNL extract showed the best bacteriostatic/bactericidal activity against Salmonella Typhimurium, Escherichia coli, and Staphylococcus aureus (MIC/MBC: 0.20/0.40, 0.20/0.40, and 0.32/0.65 mg/mL, respectively). The diameter of the zone of inhibition was larger (p < 0.05) for the 100% ethanol RNL extract (8.17 mm) against Salmonella Typhimurium, the 50% ethanol-RNL extract (11.5 mm) against E. coli, and the aqueous RNL extract (14.0 mm) against S. aureus than for any other bacterial isolate. The aqueous RNL extract strongly (p < 0.0001) inhibited the mycelial growth of Aspergillus fumigatus (100%) and Aspergillus niger (81.4%) compared with the control.

Conclusion: The results of this study suggest that RNL is a promising new natural antimicrobial agent for food preservation. To date, most research on the antimicrobial properties of natural herbs has been conducted in vitro, with few exceptions in vivo and intervention-based research.

Keywords: antimicrobial activity, Aspergillus spp., Gram-negative bacteria, Gram-positive bacteria, phytochemicals, Rumex nervosus leaves.