Molecular detection and phylogeny of Ehrlichia canis and Anaplasma platys in naturally infected dogs in Central and Northeast Thailand

Research (Published online: 20-12-2022)

16. Molecular detection and phylogeny of Ehrlichia canis and Anaplasma platys in naturally infected dogs in Central and Northeast Thailand

Andaman Purisarn, Sakulchit Wichianchot, Cherdsak Maneeruttanarungroj, Bandid Mangkit, Wuttinun Raksajit, Sarawan Kaewmongkol, Thitichai Jarudecha, Wanat Sricharern, and Rucksak Rucksaken

Veterinary World, 15(12): 2877-2889

ABSTRACT

Background and Aim: Ehrlichia canis and Anaplasma platys are tick-borne, Gram-negative bacteria that cause canine monocytic ehrlichiosis and canine cyclic thrombocytopenia, respectively. These diseases are of great importance and are distributed globally. This study aimed to create new primers for the identification of E. canis and A. platys in naturally infected dogs using polymerase chain reaction (PCR), DNA sequencing, and phylogenetic analysis using the 16S rDNA and gltA genes.

Materials and Methods: In total, 120 blood samples were collected from dogs in three different locations (Saraburi, Buriram, and Nakhon Ratchasima provinces) in Central and Northeast Thailand. The molecular prevalence of E. canis and A. platys was assessed using PCR targeting the 16S rDNA and gltA genes. All positive PCR amplicons were sequenced, and phylogenetic trees were constructed based on the maximum likelihood method.

Results: Ehrlichia canis had an overall molecular prevalence of 15.8% based on the 16S rDNA gene, compared to 8.3% based on the gltA gene. In addition, the overall molecular prevalence of A. platys using the 16S rDNA gene was 10.8%, while the prevalence rate was 5.8% using the gltA gene. Coinfection was 0.8% in Saraburi province. The partial sequences of the 16S rDNA and gltA genes of E. canis and A. platys in dogs in Central and Northeast Thailand showed 96.75%–100% identity to reference sequences in GenBank. Phylogenetic analysis of the 16S rDNA and gltA genes revealed that E. canis and A. platys sequences were clearly grouped into their own clades.

Conclusion: This study demonstrated the molecular prevalence of E. canis and A. platys in Central and Northeast Thailand. The 16S rDNA and gltA genes were useful for the diagnosis of E. canis and A. platys. Based on the phylogenetic analysis, the partial sequences of the 16S rDNA and gltA genes in E. canis and A. platys were related to prior Thai strains and those from other countries.

Keywords: 16S rDNA gene, Anaplasma platys, Ehrlichia canis, gltA gene, phylogenetic analysis.

Isolation of multidrug-resistant Escherichia coli and Salmonella spp. from sulfonamide-treated diarrheic calves

Research (Published online: 16-12-2022)

15. Isolation of multidrug-resistant Escherichia coli and Salmonella spp. from sulfonamide-treated diarrheic calves

Mohammad Amdadul Haque, Muhammad Tofazzal Hossain, Md. Shafiqul Islam, Md. Zahorul Islam, Purba Islam, Sourendra Nath Shaha, Mahmudul Hasan Sikder, and Kazi Rafiq

Veterinary World, 15(12): 2870-2876

ABSTRACT

Background and Aim: The bovine industry is threatened by one of the most serious and deadly enteric diseases, calf diarrhea, particularly in developing nations like Bangladesh. In this context, bacterial resistance to antimicrobial drugs and its detrimental consequences have become a critical public health issue that is difficult to address globally. This study aimed to isolate and identify Escherichia coli and Salmonella spp. with their antibiogram and antibiotic resistance gene detection from sulfonamide-treated diarrheic calves.

Materials and Methods: Twelve diarrheic calves suffering from calf diarrhea in a dairy farm were selected and a total of 36 fecal samples were aseptically collected directly from rectum before, during, and at the end of treatment for each calf to determine the total viable count, total E. coli count and total Salmonella count. A polymerase chain reaction was used for the specific detection of E. coli and Salmonella genus targeting fliC and invA genes, respectively. Antibiotic sensitivity test of the isolated E. coli and Salmonella spp. were performed by the disk diffusion method for eight commonly used antibiotics.

Results: A total of 36 E. coli (100%) and 12 Salmonella spp. (33%) were isolated from the samples and were confirmed by polymerase chain reaction. Total viable count was found to be ranged from 35 × 107 to 99 × 1010 colony-forming unit (CFU)/g fecal sample before starting sulfonamide treatment, 34 × 105 to 25 × 1010 CFU/g during treatment with sulfonamide, and 48 × 103 to 69 × 1010 CFU/g immediately after completion of sulfonamide treatment. Total E. coli count was found to be ranged from 4 × 104 to 36 × 1010 CFU/g, 24 × 104 to 23 × 108 CFU/g, and 13 × 104 to 85 × 1010 CFU/g, whereas total Salmonella count was found to be ranged from 16 × 106 to 18.5 × 1011 CFU/g, 15 × 104 to 44 × 107 CFU/g, and 13.2 × 105 to 21 × 1010 CFU/g fecal sample before starting sulfonamide treatment, during treatment with sulfonamide immediately after completion of sulfonamide treatment, respectively. The in vitro antibiotic sensitivity test showed that all the E. coli and Salmonella spp. isolated from diarrheic calves (100%) contained multidrug-resistant (MDR) phenotypes. Escherichia coli isolates were found 100% resistant to amoxicillin (AMX), cefuroxime, cephalexin (CN), erythromycin (ERY), and tetracycline (TET); whereas 94.4%, 86.1%, and 77.8% isolates were resistant to doxycycline (DOX), moxifloxacin (MOF), and gentamycin (GEN), respectively. In case of Salmonella isolates, all were found 100% resistant to AMX, CN, and ERY; whereas 91.7% of resistance was observed for DOX, MOF, cefuroxime, GEN, and TET. Based on the molecular screening of the antibiotic resistance genes, tetA gene was present in 83.3% of the isolated E. coli and 75% of the isolated Salmonella strains, whereas 83.3% E. coli and 79.2% Salmonella isolates contained blaTEM gene.

Conclusion: These findings suggest that MDR E. coli and Salmonella spp. might be responsible for calf scouring, which is challenging to treat with antibiotics or sulfonamide drugs alone. Therefore, it is important to check the antibiotic sensitivity pattern to select a suitable antibiotic for the treatment of calf scoring. A suitable antibiotic or combination of an antibiotic and sulfonamide could be effective against E. coli and Salmonella spp. responsible for calf scouring.

Keywords: antimicrobial resistance, calf, diarrhea, Escherichia coli, multidrug-resistant, Salmonella spp.

Selection and characterization of bacteriophages specific to Salmonella Choleraesuis in swine

Research (Published online: 16-12-2022)

14. Selection and characterization of bacteriophages specific to Salmonella Choleraesuis in swine

Pattaraporn Sriprasong, Napakhwan Imklin, and Rujikan Nasanit

Veterinary World, 15(12): 2856-2869

ABSTRACT

Background and Aim: Salmonella Choleraesuis is the most common serotype that causes salmonellosis in swine. Recently, the use of bacteriophages as a potential biocontrol strategy has increased. Therefore, this study aimed to isolate and characterize bacteriophages specific to S. Choleraesuis associated with swine infection and to evaluate the efficacy of individual phages and a phage cocktail against S. Choleraesuis strains in simulated intestinal fluid (SIF).

Materials and Methods: Three strains of S. Choleraesuis isolated from pig intestines served as host strains for phage isolation. The other 10 Salmonella serovars were also used for the phage host range test. The antibiotic susceptibility of the bacterial strains was investigated. Water samples from natural sources and drain liquid from slaughterhouses were collected for phage isolation. The isolated phages were characterized by determining the efficiency of plating against all Salmonella strains and the stability at a temperature range (4°C–65°C) and at low pH (2.5–4.0) in simulated gastric fluids (SGFs). Furthermore, morphology and genomic restriction analyses were performed for phage classification phages. Finally, S. Choleraesuis reduction in the SIF by the selected individual phages and a phage cocktail was investigated.

Results: The antibiotic susceptibility results revealed that most Salmonella strains were sensitive to all tested drugs. Salmonella Choleraesuis KPS615 was multidrug-resistant, showing resistance to three antibiotics. Nine phages were isolated. Most of them could infect four Salmonella strains. Phages vB_SCh-RP5i3B and vB_SCh-RP61i4 showed high efficiency in infecting S. Choleraesuis and Salmonella Rissen. The phages were stable for 1 h at 4°C–45°C. However, their viability decreased when the temperature increased to 65°C. In addition, most phages remained viable at a low pH (pH 2.5–4.0) for 2 h in SGF. The efficiency of phage treatment against S. Choleraesuis in SIF showed that individual phages and a phage cocktail with three phages effectively reduced S. Choleraesuis in SIF. However, the phage cocktails were more effective than the individual phages.

Conclusion: These results suggest that the newly isolated phages could be promising biocontrol agents against S. Choleraesuis infection in pigs and could be orally administered. However, further in vivo studies should be conducted.

Keywords: antimicrobials, bacteriophage, biocontrol, Salmonella Choleraesuis, swine.

Estimation of the herd-level basic reproduction number for African swine fever in Vietnam, 2019

Research (Published online: 15-12-2022)

13. Estimation of the herd-level basic reproduction number for African swine fever in Vietnam, 2019

Thi Ngan Mai, Thanh Trung Nguyen, Viet Anh Vu, Thi Ngoc Vu and Thi My Le Huynh

Veterinary World, 15(12): 2850-2855

ABSTRACT

Background and Aim: African swine fever (ASF) is a notifiable viral disease of pigs and wild boars that causes severe economic losses to the swine industry. The pig industry in Vietnam was recently attacked by the ASF virus (ASFV) for the first time in history. However, we lack information regarding the transmissibility of ASF within indoor production systems communities, such as those in Vietnam. Therefore, we aimed to estimate the basic reproduction number (R0) for ASF during the early stages of transmission between farms in indoor production system communities from local and national data in Vietnam.

Materials and Methods: The linear regression model approach for the susceptible infectious method was used in this study to estimate the transmission rate and, consequently, the R0 value.

Results: The R0 values between-farm of ASF ranged from 1.41 to 10.8 in different scenarios of infectious period duration, from 15 to 30 days at the national and local levels.

Conclusion: These results help to understand the scale and speed of ASF infection in Vietnam and to provide a scientific basis to implement control measures to restrict the spread of ASFV in other locations.

Keywords: African swine fever, basic reproduction number, indoor production, Vietnam.

Prevalence of Toxoplasma gondii, Leptospira spp., and Coxiella burnetii-associated antibodies in dairy cattle with reproductive disorders

Research (Published online: 15-12-2022)

12. Prevalence of Toxoplasma gondii, Leptospira spp., and Coxiella burnetii-associated antibodies in dairy cattle with reproductive disorders

V. Balamurugan, K. Vinod Kumar, Anusha Alamuri, P. P. Sengupta, G. Govindaraj, and B. R. Shome

Veterinary World, 15(12): 2844-2849

ABSTRACT

Background and Aim: In cattle dairy farms, abortions and other reproductive problems due to major infectious diseases are overlooked, and identifying their causative agents is very challenging without a confirmatory diagnosis. Further, a prevalence study in animals will provide important hints of pathogen reservoirs and provide necessary direction to disease burden with appropriate control and biosecurity measures at the farm level. This study aimed to estimate the prevalence of Toxoplasma gondii antibodies in dairy cattle associated with reproductive problems along with coexisting antibodies against abortifacient zoonotic (Coxiella burnetii and Leptospira spp.) pathogens.

Materials and Methods: Cattle sera (n = 246) from dairy farms (n = 35) situated in different locations in India were screened for anti-T. gondii and C. burnetii antibodies with enzyme-linked immunoassay and Leptospira spp. antibodies with microscopic agglutination test.

Results: The overall prevalence of 11.4% (95% confidence intervals [CIs]: 7.99%–15.96%) antibodies in cattle associated with reproductive problems (p < 0.021) with farm-level seropositivity of 43% was observed. Further, on analysis of screened sera, 49.8% (95% CI: 42.6%–55%) and 77.6% (95% CI: 72%–82.4%) of samples were found to be positive for C. burnetii and Leptospira spp. antibodies, respectively. Moreover, the seropositivity of 91.9% (226/246) for at least one of the screened zoonotic pathogens was observed, indicating antibodies against either of these organisms in association with reproductive disorders (p < 0.005). The percentage of cattle found to have T. gondii antibodies was only 1.8%, whereas 11.5% and 41.6% of cattle were found to have C. burnetii and Leptospira spp. antibodies, respectively. Nevertheless, the predominantly mixed infections observed were of Leptospira and C. burnetii (34.5%), followed by all three infections (4.9%); toxoplasmosis and leptospirosis (3.5%); and toxoplasmosis and Q fever (2.2%).

Conclusion: The serological detection of antibodies against these pathogens in cattle may have significant implications for the livestock industry and public health, suggesting the need for continuous surveillance and monitoring of these infections to prevent their spread.

Keywords: dairy cattle, leptospirosis, Q fever, seroprevalence, toxoplasmosis.

The reversible effects of gossypol toxicity on male pigeons' reproductive performance

Research (Published online: 13-12-2022)

11. The reversible effects of gossypol toxicity on male pigeons' reproductive performance

Suwarak Wannaratana, Wijit Banlunara, Kaj Chokeshaiusaha, and Thanida Sananmuang

Veterinary World, 15(12): 2836-2843

ABSTRACT

Background and Aim: Gossypol, a cotton seed derivative, is well known for its reversible antifertility in male reproduction across species. Its antifertility and reversibility effects on male reproductive function vary among species in dose-and time-dependent manners. In this study, the antifertility potential of gossypol in pigeons was evaluated for the first time to determine whether it might be used as a dietary supplement for pigeon population control.

Materials and Methods: Male pigeons were assigned into three experimental groups: The gossypol-treated group (n = 12), the sham control group (n = 6), and the negative control group (n = 6). There were two experimental periods: A gossypol-feeding period of 28 days and a gossypol-free period of 28 days. During the gossypol-feeding period, birds in the gossypol-treated group were fed 4 mg of gossypol extract per day. Birds in the sham control group were fed 0.5 mL of mixed ethanol and sunflower oil, while those in the negative control group were fed 0.5 mL of phosphate buffer saline. After the gossypol-feeding phase was completed, all remaining pigeons in all groups continued to receive their regular diet for an additional 28 days (gossypol-free phase). The body weight and semen quality of the birds in the experimental groups were compared to evaluate gossypol's antifertility effect.

Results: In the gossypol-treated group as compared to the control groups, the percentages of sperm motility and viability were significantly lower at 21 days, and the percentage of normal sperm morphology was significantly lower at 28 days during the gossypol-feeding period. After gossypol withdrawal, these antifertility effects were resumed and reached a comparable semen quality to the control groups within 14 days.

Conclusion: Gossypol supplementation (4 mg/day for 28 days) could lower male pigeons' reproductive performance in terms of sperm motility, viability, and sperm morphology. Such infertility was, however, reversible within 14 days after gossypol withdrawal without any side effects on the pigeons, suggesting its application as a safe contraceptive feeding for male pigeons.

Keywords: gossypol, pigeon, sperm morphology, sperm motility, sperm viability.

Seroprevalence of nasal myiasis in camels determined by indirect enzyme-linked immunosorbent assay utilizing the most diagnostic Cephalopina titillator larval antigens

Research (Published online: 13-12-2022)

10. Seroprevalence of nasal myiasis in camels determined by indirect enzyme-linked immunosorbent assay utilizing the most diagnostic Cephalopina titillator larval antigens

Noha M. F. Hassan, Doaa Sedky, Nadia M. T. Abu El Ezz, and Eman E. El Shanawany

Veterinary World, 15(12): 2830-2835

ABSTRACT

Background and Aim: Nasal myiasis is a serious parasitic disease among camels caused by Cephalopina titillator larvae that negatively affect animal health and production globally. The diagnosis of the infestation relies on postmortem examination of the head region, which considers a cause impeding treatment of live animals and may be misdiagnosed as central nervous system disorders. This study aimed to identify the most diagnostic larval antigen with the capacity for monitoring C. titillator infestation, and to estimate the seroprevalence of nasal myiasis in camels in Egypt, using indirect enzyme-linked immunosorbent assay (ELISA).

Materials and Methods: Three hundred and six male camels of Egyptian and Sudanese breeds, aged 2–5 years, were clinically evaluated for respiratory and/or nervous disorders in Cairo Governorate, Egypt. At the time of slaughter, blood samples were collected from all examined animals. The postmortem examination of 38 animals was conducted. Salivary glands, hemolymph, and somatic antigens were extracted from the second and third larval instars.

Results: The results revealed that the salivary gland antigen was the most potent antigen in detecting C. titillator specific total IgG antibodies compared to haemolymph and crude somatic antigens. Using receiver-operating characteristic curves and area under the curve, the salivary gland antigen had a sensitivity of 91.67% and a specificity of 92.31%, respectively. It has the highest positive predictive value, 95.7%, and negative predictive value, 85.7%. However, using somatic and hemolymph antigens revealed a sensitivity of 79.17% and 70.83% and a specificity of 76.9% and 84.6%, respectively. There was complete concordance between ELISA results and autopsy findings (true positive). One hundred and forty out of 306 (45.8%) camel serum samples were found to contain C. titillator.

Conclusion: This study demonstrated that salivary gland antigen is more effective than somatic and hemolymph antigens in accurately detecting nasal myiasis in camels. In addition, determining the seroprevalence of nasal myiasis with the salivary gland antigen through indirect ELISA revealed that it is a prevalent disease among camels in Egypt. Periodic surveillance of the C. titillator prevalence is necessary for effective management and control measures.