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Background: Chikungunya virus (CHIKV) has reemerged as a major public health concern, causing chikungunya fever with increasing cases and neurological complications. Methods: In the present study, we investigated a low-passage human isolate of the East/ Central/South African (ECSA) lineage of CHIKV strain LK(EH)CH6708, which exhibited a mix of small and large viral plaques. The small and large plaque variants were isolated and designated as CHIKV-SP and CHIKV-BP, respectively. CHIKV-SP and CHIKV-BP were characterized in vitro and in vivo to compare their virus production and virulence. Additionally, whole viral genome analysis and reverse genetics were employed to identify genomic virulence factors. Results: CHIKV-SP demonstrated lower virus production in mammalian cells and attenuated virulence in a murine model. On the other hand, CHIKV-BP induced higher pro-inflammatory cytokine levels, compromised the integrity of the blood–brain barrier, and led to astrocyte infection in mouse brains. Furthermore, the CHIKV-SP variant had limited transmission potential in Aedesalbopictus mosquitoes, likely due to restricted dissemination. Whole viral genome analysis revealed multiple genetic mutations in the CHIKV-SP variant, including a Glycine (G) to Arginine (R) mutation at position 55 in the viral E2 glycoprotein. Reverse genetics experiments confirmed that the E2-G55R mutation alone was sufficient to reduce virus production in vitro and virulence in mice. Conclusions: These findings highlight the attenuating effects of the E2-G55R mutation on CHIKV pathogenicity and neurovirulence and emphasize the importance of monitoring this mutation in natural infections. [ABSTRACT FROM AUTHOR]

Background and Aims: Methicillin-resistant Staphylococci (MRS) seriously threatens animal and human health. Repeated antibiotic use allows the bacteria to develop resistance to several antibiotic classes and become multidrug-resistant (MDR). Canine pyoderma, a common skin condition in dogs, is mainly caused by Staphylococci, including MRS. Detecting this infection in all canine populations is crucial to develop a proper preventive plan. This study estimated the prevalence, antibiogram, and risk factors of MRS in canine patients at a referral animal hospital in Khon Kaen, Thailand. Materials and Methods: Skin swabs and relevant information were collected from 56 client-owned dogs that visited the hospital from September 2019 to September 2020. Staphylococci colonies were subjected to molecular identification and antibiotic susceptibility tests using an automated system (VITEK®2). These colonies were also genetically identified using multiplex-polymerase chain reaction (PCR) and sequencing. The mecA gene, encoding methicillin resistance, was detected using simplex-PCR. The risk factors of MRS infection and their association with MRS infection were analyzed using logistic regression and the Chi-square test, respectively. Results: The prevalence of MRS was found to be 35.7% (20/56 dogs). By species, methicillin-resistant Staphylococcus pseudintermedius was found in 24 of 104 isolates (23.1%), and all samples were MDR. Receiving systemic antibiotics in the past 6 months was a major risk factor associated with MRS infection (p < 0.05; odds ratio (OR) > 1). In addition to the MRS isolates, the mecA gene was also detected in methicillin-susceptible Staphylococci isolates. This might be because of the high expression of blaI, and mutations in c-di-AMP cyclase DacA, RelA, and Fem proteins. Conclusion: A high prevalence of MRS and MDR was observed in the studied population, which might be potentially due to improper antibiotic use by the owners and horizontal transfer of drug-resistance genes. [ABSTRACT FROM AUTHOR]

Aim: This study aims to determine the prevalence of Cryptosporidium spp. infection and to identify the species of Cryptosporidium spp. in newborn dairy calves between December 2016 and March 2017 in Muang District, Khon Kaen Province, Thailand. Materials and Methods: A total of 200 fecal samples from newborn dairy calves of the ages 1 day up to 28 days were collected and the presence of Cryptosporidium oocysts was examined microscopically using the modified Kinyoun's acidfast staining technique. Then, Cryptosporidium species were identified using nested polymerase chain reaction amplification of 18S rRNA gene and sequencing. Results: The modified Kinyoun's acid-fast staining revealed the presence of Cryptosporidium oocysts in 51% (102/200). Sequence analysis of the 18S rRNA gene identified two species, namely, Cryptosporidium bovis (n=11) and Cryptosporidium ryanae (n=11) and one isolated strain could not be identified. Conclusion: This study indicated that newborn dairy calves aging up to 4 weeks were highly infected with Cryptosporidium spp., and the infection mostly occurred in diarrheic dairy calves. This is the first report of Cryptosporidium in dairy calves in Khon Kaen Province and the results provide baseline information for further studies and control of Cryptosporidium infection in dairy calves in the study area. [ABSTRACT FROM AUTHOR]

One hundred and twenty chicken samples from feces (n = 80), the carcass surface at slaughter at 2 meat chicken farms (n = 20), and retail chicken meat from 5 markets (n = 20) collected during 2018 and 2019 were examined for the prevalence of plasmid-mediated quinolone resistance (PMQR) in Escherichia coli. We detected qnrS -positive E. coli in a total of 74 samples from feces (n = 59), the carcass surface (n = 7), and retail meat (n = 8). These 74 qnrS -positive isolates were tested for antimicrobial susceptibility to determine the minimum inhibitory concentrations (MICs) of certain antimicrobials and genetically characterized. Ampicillin-resistance accounted for 71 of the 74 isolates (96%), followed by resistance to oxytetracycline (57/74; 77%), enrofloxacin (ERFX) (56/74; 76%), sulfisoxazole (SUL) (56/74; 76%), trimethoprim (TMP) (49/74; 66%), and dihydrostreptomycin (48/74; 65%). All farm-borne SUL- and TMP-resistant isolates except one were obtained from samples from farm A where a combination of sulfadiazine and TMP was administered to the chickens. Concentrations of ERFX at which 50 and 90% of isolates were inhibited were 2 μg/mL and 32 μg/mL, respectively. Diverse pulsed-field gel electrophoresis (PFGE) patterns of Xba I-digested genomic DNA were observed in the qnrS -positive isolates from fecal samples. Several isolates from feces and the carcass surface had identical Xba I-digested PFGE patterns. S1-nuclease PFGE and Southern blot analysis demonstrated that 7 of 11 dfrA13 -positive fecal isolates carried both the qnrS and dfrA13 genes on the same plasmid, and 2 of 3 dfrA1 -positive isolates similarly carried both qnrS and dfrA1 on the same plasmid, although the PFGE patterns of Xba I-digested genomic DNA of the isolates were different. These results suggest that the qnrS gene is prevalent in chicken farms via horizontal transfer of plasmids and may partly be co-selected under the use of TMP. [ABSTRACT FROM AUTHOR]

Human enterovirus 71 (HEV71) is the causative agent of hand, foot, and mouth disease and associated acute neurological disease. At present, little is known about the genetic determinants of HEV71 neurovirulence. Studies of related enteroviruses have indicated that the untranslated regions (UTRs), which control virus-directed translation and replication, also exert significant influence on neurovirulence. We used an infectious cDNA clone of a subgenogroup B3 strain to construct and characterize chimeras with 5′- and 3′-UTR modifications. Replacement of the entire HEV71 5′ UTR with that of human rhinovirus 2 (HRV2) resulted in a small reduction in growth efficiency in cells of both nonneuronal (rhabdomyosarcoma) and neuronal (SH-SY5Y) origin due to reduced translational efficiency. However, the introduction of a 17-nucleotide deletion into the proximal region of the 3′ UTR significantly decreased the growth of HEV71-HRV2 in SH-SY5Y cells. This observation is similar to that made with stem-loop domain Z (SLD Z)-deleted coxsackievirus B3-HRV2 5′-UTR chimeras reported previously and provides the first evidence of a potentially functional SLD Z in the 3′ UTR in human enterovirus A species viruses. We further showed that the cell-specific growth impairment was caused by the synergistic effects of cis-acting UTR control elements on different stages of the virus life cycle. These chimeras will further improve our understanding of the control of HEV71 replication and its relationship to neurovirulence. [ABSTRACT FROM AUTHOR]

Eighty isolates of Riemerella anatipestifer representing 71 outbreaks of riemerellosis in Thailand between 1994 and 1999 were serotyped using the gel diffusion precipitin test. Based on the precipitation patterns, 25 serological profiles containing one to three antigenic determinants were recognized. Heat-stable antigens of the organism reacted with antisera raised against 16 known serotypes and an untypable strain 698/95. The most prevalent serotype appeared to be serotype 7, followed by serotypes 5, 10, 21 and 1. Further study demonstrated that the untypable strain probably represents a new serotype. Analysis of the polymerase chain reaction-amplified rrs genes for restriction fragment length polymorphisms verified the inclusion of strain 698/95 within the species R. anatipestifer and supported earlier work excluding strain 670/89, which had originally been designated the reference strain of serotype 20. Therefore, it is suggested that the strain 698/95 could be adopted as a replacement for the reference strain of serotype 20. Attention should be paid to strains with multiple antigenic factors as they may be useful for the preparation of vaccines. [ABSTRACT FROM AUTHOR]

Background and Aim: Mastitis is an important disease that can reduce milk production and farmer income as well as negatively affect human health. This study aimed to summarize dairy mastitis in Indonesia, both subclinical mastitis (SCM) and clinical mastitis (CM), and its prevalence in different provinces, the diagnostic methods, and the animal species. Materials and Methods: Relevant studies on mastitis in dairy animals in Indonesia were obtained from PubMed, Scopus, ProQuest, Google Scholar, and Garuda. The title and abstract were screened for the eligibility of the studies. The full text of the selected studies was assessed and the data were extracted for analysis. To determine the pooled estimate of the prevalence of mastitis, a random-effects model was performed using the "Meta" and "Metaphor" packages in the R software version 4.2.2. The heterogeneity of several characteristics (mastitis type, provinces, animal species, and diagnostic methods) was evaluated through subgroup meta-analysis. Meta-regression analysis was conducted to assess the trend of mastitis prevalence reports over time. Publication bias was evaluated using Egger's test and a funnel plot. Results: A total of 735 studies were retrieved for the title and abstract screening, which resulted in the final selection of 37 studies with a total of 6050 samples for meta-analysis. The pooled estimate of mastitis prevalence in dairy animals in Indonesia was 59.44% (95% confidence interval [CI], 52.39%-66.49%). Based on mastitis type, SCM had a significantly higher prevalence than CM (58.24% [95% CI, 51.26%-65.23%] vs. 3.31% [95% CI, 1.42%-5.19%]). No significant difference was observed in the analysis of other subgroups. Among provinces, Central Java had the highest prevalence (66.62% [95% CI, 49.37%-83.87%]), whereas Yogyakarta had the lowest (41.77% [95% CI, 14.96%-68.58%]). Based on animal species, cow and goat had a prevalence of 63.42% (95% CI, 55.97%-70.86%) and 44.96% (95% CI, 28.26%-61.66%), respectively. Based on the diagnostic method, the California mastitis test resulted in 60.08% (95% CI, 52.11%- 68.06%) and the Institut Pertanian Bogor test, 56.00% (95% CI, 41.20%-70.81%). No significant change in the prevalence of mastitis in Indonesia was observed from 2003 to 2022. Conclusion: This study demonstrates that the pooled estimate of mastitis prevalence in dairy animals in Indonesia is >50%. Based on subgroup analysis, SCM had a higher prevalence than CM; however, the prevalence between provinces, detection methods, and animal species in the 2003-2022 periods was not significantly different. A mastitis control strategy needs to be developed to reduce the prevalence of mastitis and further loss in milk production. [ABSTRACT FROM AUTHOR]