Emerging Trends in the Epidemiology of COVID-19: The Croatian ‘One Health’ Perspective

Abstract

During the four pandemic waves, a total of 560,504 cases and 10,178 deaths due to COVID-19 were reported in Croatia. The Alpha variant, dominant from March 2021 (>50% of positive samples), was rapidly replaced by Delta variants (>90%) by August 2021. Several seroprevalence studies were conducted in different populations (general population, children/adolescents, professional athletes, healthcare workers, veterinarians) and in immunocompromised patients (hemodialysis patients, liver/kidney transplant recipients). After the first pandemic wave, seroprevalence rates of neutralizing (NT) antibodies were reported to be 0.2–5.5%. Significantly higher seropositivity was detected during/after the second wave, 2.6–18.7%. Two studies conducted in pet animals (February-June 2020/July–December 2020) reported SARS-CoV-2 NT antibodies in 0.76% of cats and 0.31–14.69% of dogs, respectively. SARS-CoV-2 NT antibodies were not detected in wildlife. Environmental samples taken in the households of COVID-19 patients showed high-touch personal objects as most frequently contaminated (17.3%), followed by surfaces in patients’ rooms (14.6%), kitchens (13.3%) and bathrooms (8.3%). SARS-CoV-2 RNA was also detected in 96.8% affluent water samples, while all effluent water samples tested negative. Detection of SARS-CoV-2 in humans, animals and the environment suggests that the ‘One Health’ approach is critical to controlling COVID-19 and future pandemics.

Genomic and Temporal Trends in Canine ExPEC Reflect Those of Human ExPEC

“…However, there is the wide variety of pathogens that may transfer between humans and dogs, posing health risks to both ( 6 ). The benefits of dog ownership must therefore be weighed with the possible zoonotic disease implications that may be associated with these relationships ( 7 – 9 ).…”

SARS-CoV-2 Omicron Variant in Croatia—Rapid Detection of the First Case and Cross-Border Spread

“…Namely, the appearance of the Alpha variant (Phylogenetic Assignment of Named Global Outbreak (PANGO) lineage B.1.1.7) [ 18 , 19 , 20 ] in the population in February 2021 announced the beginning of the third epidemic wave, while the presence of the Delta variant (PANGO lineage B.1.617.2) [ 18 , 19 , 20 ] in June 2021 led to the fourth epidemic wave. Until the end of August 2021, the Delta variant with its sub-lineages [ 18 , 19 , 20 ] constituted more than 98% of all SARS-CoV-2 positive samples, while the Beta and Gamma variants were detected sporadically and connected with travellers to areas with a high prevalence and their contacts [ 33 ].…”

Field evaluation of COVID-19 rapid antigen test: Are rapid antigen tests less reliable among the elderly?

“…During the study period, declining numbers of tested and confirmed COVID-19 cases were observed, which can be attributed to the epidemiological situation in Croatia characterized with declining incidence and prevalence of COVID-19[ 4 , 10 ]. The main strength of this in-field evaluation is the sample size, whereas the limitations include various swab-takers and six RAT operators/interpreters; however, they were always competent and well-educated personnel ( e.g., laboratory personnel or medical doctors).…”

“…The national recommendation that negative RAT results in symptomatic patients suggestive of COVID-19 should be further tested by RT-PCR seems like a good solution because negative RAT results do not rule out the infection, especially in the high prevalence settings during study period[ 4 ]. Identifying and confirming COVID-19 in symptomatic persons is important to provide appropriate care and implement public health measures without delay[ 11 ].…”

“…RAT testing should be conducted by trained personnel within the first 5-7 d following the onset of symptoms[ 3 ]. Since the molecular capacity is difficult to scale-up and there was a need to expand the COVID-19 testing capacity due to the increasing numbers of cases at the end of 2020, Croatia implemented the RAT as a part of the national strategy for handling the SARS-CoV-2 pandemic[ 4 ].…”