Papers by Kaspars Kovalenko
Pharmacokinetic and Pharmacodynamic Evaluations of Levofloxacin in Broiler Chickens
Campylobacteriosis in humans is caused by thermophilic Campylobacter spp., most commonly by C. je... more Campylobacteriosis in humans is caused by thermophilic Campylobacter spp., most commonly by C. jejuni. The aim of the present study was to determine the effect of the average air temperature of sampling day on the occurrence of Campylobacter spp. in broiler chicken production at slaughterhouses and retail level in Latvia. Poultry samples originated from the two biggest Latvian broiler slaughterhouses. In all, 240 fresh broiler chicken neck skins, 240 intact broiler chicken intestines and 240 fresh broiler chicken carcasses were collected during the year 2010. In total, 68.8% of the intestine samples, 60.8% of the neck skin samples, and 56.3% of carcasses were positive for Campylobacter spp. with a high correlation (r≥0.65; p<0.05) of air temperature on day of sampling.
Proceedings of the Latvian Academy of Sciences. Section B, Natural, Exact and Applied Sciences, Oct 1, 2021
Q fever is an important zoonotic disease worldwide. The main sources of human infection are inhal... more Q fever is an important zoonotic disease worldwide. The main sources of human infection are inhalation of aerosols containing Coxiella burnetii bacteria and exposition to infected materials during parturition or slaughtering. The high-risk group includes people who work directly with infected livestock, such as farmers, veterinarians, veterinary medicine students, slaughterhouse and laboratory staff. Here we present a pilot study of risk-group human seroprevalence to C. burnetii in Latvia. The study included 240 sera samples -190 from the risk groups and 50 from the control group. Samples were tested with Coxiella burnetii (Q-fever) Phase 1 and 2 IgG ELISA kits. All sera from the control group were negative. The seroprevalence among risk group persons was 8. 04-11.54%. No statistically significant differences were observed between genders. The highest percentage of seropositive and equivocal sera samples (25%) were detected in age categories 39-48 years and 49-58 years. Working as a practicing veterinarian or former veterinarian was the only risk factor identified as statistically significant, and belonging to the risk group in general. The geographical distribution of seropositive risk group participants indicated that they tend to located more in the northern, central, and eastern part of the country.
FoodBalt .., Apr 27, 2017
Identification of freshwater fish microflora is an important tool for evaluation of quality and s... more Identification of freshwater fish microflora is an important tool for evaluation of quality and safety of fish intended for human consumption. The aim of the present study was to detect the microflora of freshwater fish caught by fishermen. Altogether, 23 samples of freshwater fish were collected from fishermen from two different water sources -Driksna river and pond in Dobele. For detection of microbiological contamination, fish samples were tested for the total bacterial count (TBC), coliforms, Enterobacteriaceae and zoonotic pathogenic microorganisms -Salmonella spp., Listeria spp., and Yersinia spp. Identification of bacterial species was carried out by the MALDI-TOF MS Biotyper. TBC ranged from 2.7 to 4.78 log10 CFU g -1 and 3.68 to 4.11 log10 CFU g -1 , coliforms from 2.55 to 4.10 log10 CFU g -1 and 1.38 to 2.73 log10 CFU g -1 , Enterobacteriaceae from 1.95 to 4.05 log10 CFU g -1 and 1.72 to 2.69 log10 CFU g -1 in pond and river fish samples, respectively. Between two fishing locations, fish caught in pond carried the significantly higher number of TBC, coliforms and Enterobacteriaceae than fish from the river (P>0.05). Freshwater fish microflora consisted of Pseudomonas spp. (55%), Serratia spp. (7%), Candida spp. (6%), Rahnella spp. (7%), Pantoea spp. (9%), Aeromonas spp. (5%), Buttiauxella spp. (8%), Stenotrophonomas spp. (2%) and Enterobacter spp. (1%). Salmonella spp., Listeria spp. and Yersinia spp. were not identified. Despite the human pathogenic microorganisms were not identified in the present study, the composition of microflora and especially the abundance of Pseudomonas spp. indicates that the fish are prone to spoilage process development that potentially may alter the quality of freshwater fish meat.
Prevalence and Antimicrobial Resistance of <i>Escherichia coli</i>, <i>Enterococcus</i> spp. and the Major Foodborne Pathogens in Calves in Latvia
Foodborne Pathogens and Disease, 2019
The aim of the present study was to detect the prevalence and antimicrobial resistance of fecal i... more The aim of the present study was to detect the prevalence and antimicrobial resistance of fecal indicators and major foodborne pathogens in feces of calves and to identify the factors associated with increased prevalence of resistant bacteria on farms. Altogether, 180 rectal swabs were collected from 18 farms in Latvia. Samples were investigated to detect the prevalence and antimicrobial resistance of Escherichia coli, Enterococcus spp., Listeria monocytogenes, Yersinia enterocolitica, Salmonella spp., Staphylococcus aureus, and Campylobacter spp. Among all, 64% (74/110) of commensal E. coli, 100% (78/78) Enterococcus faecalis and 96% (22/23) Enterococcus faecium isolates were resistant at least to one antibiotic. The prevalence of extended-spectrum β-lactamase (ESBL)/AmpC-producing E. coli were 11.1% (20/180) with blaCTX-M, blaTEM, and blaCMY genes identified. Campylobacter jejuni (12.8%, 23/180) and Campylobacter coli (2.8%, 5/180) were the most resistant to tetracycline (61%, 14/23; 100%, 5/5) and fluoroquinolones (61%, 14/23; 100%, 5/5). Prevalence of L. monocytogenes was 0.6% (1/180) and S. aureus 1.7% (3/180). All samples were Salmonella and Y. enterocolitica negative. Farm size, bought calves, contact with other calves, and antimicrobial treatment of cows were associated with increased prevalence of resistant E. coli and Enterococcus spp. Despite the low overall usage of antimicrobials in Latvia, the high rates of antimicrobial resistance in fecal indicators and Campylobacter, in addition to the high prevalence of ESBL-producing E. coli, highlights the necessity for the prudent use of antimicrobials in dairy farms in Latvia.
Annals of Agricultural and Environmental Medicine, May 11, 2017
Introduction and objective. Salmonella is a foodborne pathogen which causes gastrointestinal illn... more Introduction and objective. Salmonella is a foodborne pathogen which causes gastrointestinal illness in consumers, and exhibits resistance to antimicrobials of veterinary and clinical significance. The aim of this study is to detect the prevalence and antimicrobial resistance of Salmonella isolates from meat in Latvia. Materials and method. A total of 3,152 samples of raw and ready-to-eat (RTE) meats were collected during the official control and in-house control procedures in 2015. Samples were tested in accordance with ISO 6579:2002. All S. Typhimurium, S. Enteritidis and other isolates recovered from the official control samples (S. Derby, S. Give) were tested for antimicrobial resistance. The minimum inhibitory concentration (MIC) values were investigated in line with the requirements of the European Committee on Antimicrobial Susceptibility Testing (EUCAST). Results. The prevalence of Salmonella was 0.8% (25/3152). The highest prevalence (1.5%) of Salmonella was found in minced meat and meat preparations (7/481), while the lowest (0%) in frozen meat and meat preparations (0/349) and RTE meats (0/364). The most common serovars were S. Typhimurium (36%, 9/25) and S. Derby (32%, 8/25). In total, 62% (13/21) of Salmonella isolates were resistant to at least one antimicrobial agent. Altogether, 40% (8/20) of isolates were resistant to sulfamethoxazole, 25% (5/20) to nalidixic acid, ciprofloxacin, ampicillin and 20% (4/20) to tetracycline. All isolates were susceptible to ceftazidime, cefotaxime, meropenem, azithromycin and tigecycline. S. Typhimurium exhibited antimicrobial resistance more often (87.5%) than other serovars. The study shows that the presence of Salmonella in meat, together with the high prevalence of resistant strains, is a significant public health related issue in Latvia.
Proceedings of the Latvian Academy of Sciences. Section B, Natural, Exact and Applied Sciences, Apr 1, 2022
The goal of this study was to estimate the prevalence of Q-fever infection in Latvia among dairy ... more The goal of this study was to estimate the prevalence of Q-fever infection in Latvia among dairy cattle in 2018-2020, in comparison with that in 2012-2015. The shedding of Coxiella burnetii DNA in milk was assessed. Screening of blood samples of abortion cases for the presence of antibodies against Q-fever and testing of aborted fetuses for C. burnetii DNA were also carried out. Additionally, serum samples from clinically healthy cattle, sheep and goat were included. Overall, 18.34% of milk samples were positive, representing 11.02% of all tested sheds. In total, 20.62% of serum samples from the cattle that suffered abortions were positive or suspicious, representing 12.63% of all sheds. Only 3.33% of serum samples from clinically healthy cattle and 3.42% from sheep and goat were positive. The highest proportion of serologically positive and suspicious samples was observed in cattle that suffered abortion with age from three to nine years, and in the first and third gestation period. One dominant genotype of C. burnetii (MST61) was detected. Ruminant import from abroad was identified as a significant risk factor, as well as the dairy cattle population density.
Rural Sustainability Research
Q fever is a widespread disease affecting reproduction in dairy cattle. Several risk factors can ... more Q fever is a widespread disease affecting reproduction in dairy cattle. Several risk factors can increase the possibility of the herd becoming infected and the persistence of infection. The aim of this study was to characterise the dynamics of C. burnetii infection in affected herds and to evaluate reproduction problems and risk factors using a questionnaire within infected and infection-free dairy herds. In total, 25 farms that were serologically positive or shedding C. burnetii DNA in milk and 14 C. burnetii infection-free farms in Latvia answered the questionnaire. Ten positive herds were studied by testing individual blood and milk samples from up to 10 animals at two times separated by 7.5 to 13 months. The number of serologically positive and suspicious animals was higher in the second sampling even though several animals were culled. In the positive herds, the percentage of dystocia, stillborn calves and abortions during the last year was significantly (p=0.001; 0.01; 0.005, ...
Frontiers in Veterinary Science
Research for Rural Development, 2021
Feline coronavirus (FCoV) is ubiquitous in the domestic cat (Felis catus) population. The aim of ... more Feline coronavirus (FCoV) is ubiquitous in the domestic cat (Felis catus) population. The aim of this study was to determine the prevalence and potential predisposing factors of FCoV in cats of an animal shelter in Latvia and to compare the prevalence between cats in the quarantine area and resident cats in the adoption area. Oropharyngeal and faecal swabs and blood samples were collected from 40 domestic shorthair cats from an animal shelter in Jelgava, Latvia. Swabs were analyzed for FCoV RNA by reverse transcriptase-polymerase chain reaction (RT-PCR). Blood serum samples were tested for FCoV specific antibodies by indirect enzyme-linked immunosorbent assay (ELISA). FCoV RT-PCR positivity in oropharyngeal and rectal swabs was 7.5% (3/40) and 72.5% (29/40), respectively. Additionally, FCoV seroprevalence was 67.5% (27/40). The proportion of cats shedding FCoV within the adoption (72.7%) and quarantine (72.2%) areas was similar (p = 0.55). The prevalence of FCoV faecal shedding in y...
Agriculture and Food, 2016
Changes in consumer lifestyle, which requires a convenient food consumption, aids in the growing ... more Changes in consumer lifestyle, which requires a convenient food consumption, aids in the growing demand for ready to eat meals. It is important to ensure not only healthy but also microbiologically safe ready to eat meals. Thermal treatment is intended to ensure industrial sterility of the products. Commercially sterile food is processed in packaging, and the temperature is the key to reduce the amount of microorganisms in the food to a level where the food is free from viable forms of microorganisms, including spores. The aim of this study was to determine the efficiency of thermal treatment on functional ready to eat meals in flexible packaging. Five types of ready to eat meals were prepared for this study (control samples potatoes and potatoes with chicken fillet, and functional ready to eat meals potatoes with amaranth, quinoa, and bulgur). Ready to eat meals were filled in pouches of two different packaging materials (PA/PE and PET/ALU/PA/PP), hermetically sealed under vacuum a...
Agronomy research, 2010
The present study gives a review of the contaminati on and health risks related to Campylobacter ... more The present study gives a review of the contaminati on and health risks related to Campylobacter spp. and L. monocytogenes in the Estonian and Latvian food supply. Campylobacteriosis and human listeriosis ar e important zoonotic diseases. Therefore, biosecurity measures at the farm level a nd Good Hygiene Practices at the industry level must be strictly followed. Further i mprovements in the state surveillance and food industry self-control systems are needed b oth in Estonia and Latvia.
Frontiers in Veterinary Science, 2021
The COST action “Standardising output-based surveillance to control non-regulated diseases of cat... more The COST action “Standardising output-based surveillance to control non-regulated diseases of cattle in the European Union (SOUND control),” aims to harmonise the results of surveillance and control programmes (CPs) for selected cattle diseases to facilitate safe trade and improve overall control of cattle infectious diseases. In this paper we aimed to provide an overview on the diversity of control for these diseases in Europe. A selected cattle disease was defined as an infectious disease of cattle with no or limited control at EU level, which is not included in the European Union Animal health law Categories A or B under Commission Implementing Regulation (EU) 2020/2002. A CP was defined as surveillance and/or intervention strategies designed to lower the incidence, prevalence, mortality or prove freedom from a specific disease in a region or country. Passive surveillance, and active surveillance of breeding bulls under Council Directive 88/407/EEC were not considered as CPs. A q...
Journal of Veterinary Research, 2021
Introduction Q fever in dairy cattle has been investigated in Latvia since 2012. In 2015, 10.7% o... more Introduction Q fever in dairy cattle has been investigated in Latvia since 2012. In 2015, 10.7% of farms tested positive for the DNA of C. burnetii, its aetiological agent, in bulk tank milk. The presence of C. burnetii DNA and infectious bacteria in dairy products has been assessed in several countries, and because Latvian milk may contain them, parallel assessment in this country is recommended. Accordingly, the present study tested shop and farm retail dairy products from Latvia and included foreign products for comparison. Material and Methods Investigation was carried out of 187 samples of a diverse range of dairy products from 41 Latvian milk producers. Twenty-six comparable samples pooled from Estonia, France, Germany, Greece, Italy, Lithuania, the Netherlands, Poland and Spain were also included. The all-countries total number of fermented milk products was 160. Special attention was paid to products that could be more attractive to children because of their added chocolate,...
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Papers by Kaspars Kovalenko