Influenza vaccine effectiveness estimates in Croatia in 2010-2011: a season with predominant circulation of A(H1N1)pdm09 influenza virus.

This is a retrospective study using the test-negative case-control method to estimate seasonal 2010-2011 influenza vaccine effectiveness (VE) in Croatia. Of patients consulting a physician for influenza-like illness (ILI) and for whom a swab was taken, we compared RT-PCR influenza-positive and RT-PCR influenza-negative patients. We used a structured questionnaire and physicians' records to obtain information on vaccination status and potential confounders. We conducted a complete case analysis using logistic regression to measure adjusted VE overall, against A(H1N1)pdm09 and in age groups. Out of 785 interviewed patients, 495 eligible patients were included in the study, after applying exclusion criteria [217 cases, of which 92·6% were A(H1N1)pdm09 positive, 278 controls]. Crude VE was 31·9% [95% confidence interval (CI) -40·9 to 67·1] and adjusted VE was 20·7% (95% CI -71·4 to 63·3), with higher VE in youngest and oldest age groups. Results from this first VE study in Croatia suggest a low to moderate VE for the 2010-2011 season. Studies year on year are needed with a greater sample size to provide more precise estimates, and also by age group and risk groups for vaccination.

First evidence of simultaneous occurrence of West Nile virus and Usutu virus neuroinvasive disease in humans in Croatia during the 2013 outbreak.

PURPOSE: We report on first evidence of simultaneous occurrence of West Nile virus (WNV) and Usutu virus (USUV) neuroinvasive infection in humans in Croatia during the transmission season 2013. METHODS: From June to December 2013, a total of 95 patients with clinically suspected WNV infection (WNV fever and neuroinvasive disease) were tested for WNV IgM/IgG antibodies using enzyme-linked immunosorbent assay. Twenty-six reactive samples were further tested by virus neutralization test for confirmation. RESULTS: WNV neuroinvasive infection was confirmed in 20 patients, while in three patients USUV neutralizing antibodies were detected. Cases occurred during the 11-week interval (from 24 July to 07 October 2013). Both WNV and USUV cases were distributed in three north-western Croatian counties. In addition to human cases, recent asymptomatic WNV infection (detection of IgM antibodies) was recorded in 9/3,460 (0.3 %) tested sentinel horses. Infected animals were recorded in two eastern and one north-western county. CONCLUSIONS: Our results indicate co-circulation of WNV and USUV in Croatia. WNV infection could be misdiagnosed with other emerging infectious diseases presenting with neurological symptoms such as USUV infection.

Outbreak of hand, foot and mouth disease caused by Coxsackie A16 virus in a childcare centre in Croatia, February to March 2011.

We describe an outbreak of hand, foot and mouth disease (HFMD) in a childcare centre in a district of Zagreb county, north-west Croatia. A total of eleven cases of HFMD occurred in the childcare centre and another nine were reported from nearby areas in the district. Coxsackie A16 virus was diagnosed in 13 clinical specimens obtained from 11 symptomatic and asymptomatic children. All cases resolved without complications.

Autochthonous dengue fever in Croatia, August-September 2010.

After information about a dengue case in Germany acquired in Croatia, health professionals and the public in Croatia were alerted to assess the situation and to enhance mosquito control, resulting in the diagnosis of a second case of autochthonous dengue fever in the same area and the detection of 15 persons with evidence of recent dengue infection. Mosquito control measures were introduced. The circumstances of dengue virus introduction to Croatia remain unresolved.

Spotlight on measles 2010: excretion of vaccine strain measles virus in urine and pharyngeal secretions of a child with vaccine associated febrile rash illness, Croatia, March 2010.

We describe excretion of measles vaccine strain Schwarz in a child who developed a febrile rash illness eight days after primary immunisation against measles, mumps and rubella. Throat swabs and urine specimens were collected on the fifth and sixth day of illness, respectively. Genotyping demonstrated measles vaccine strain Schwarz (genotype A). If measles and rubella were not under enhanced surveillance in Croatia, the case would have been either misreported as rubella or not recognised at all.

A measles outbreak in Croatia, 2008.

We report an outbreak of measles in Croatia, involving 49 cases with onset of symptoms between end of April and June 2008. Cases occurred in Zagreb and Slavonski Brod but investigations indicated a common epidemiological link between these two geographically separate regions.

Transmission of the L-Zagreb mumps vaccine virus, Croatia, 2005-2008.

We report on three cases of symptomatic transmission of the L-Zagreb mumps vaccine virus from three vaccinated children to five adult contacts. The five contact cases were parents of the vaccinated children and presented with parotitis and in one case also with aseptic meningitis. The etiology of the contacts' illness was determined by viral culture, genomic sequencing, serology and epidemiological linking. Two of the vaccinated children developed vaccine associated parotitis as an adverse event three weeks following immunization. Symptoms in contact cases developed five to seven weeks after the vaccination of the children. The five contact cases, as well as the three children with adverse events recovered completely. The children had been vaccinated with MMR vaccine produced by the Institute of Immunology Zagreb, each of them with a different lot. One of the possible explanations for these adverse events is that the very low levels of wild mumps virus circulation in the last decade, combined with waning immunity in those who received one dose of vaccine or suffered from mumps in childhood, resulted in susceptible young adults and that this unique epidemiological situation allows us to detect horizontal transmission of mumps vaccine virus.

Enumeration of haemagglutinin-specific CD8+ T cells after influenza vaccination using MHC class I peptide tetramers.

With emergence of MHC class I tetramers loaded with CD8+ T-cell viral epitopes, it is possible to study virus-specific CD8 cells in humans during infection and after vaccination. MHC class I tetramers was used to detect the frequency of haemagglutinin (HA)-specific T cells in 26 healthy influenza-vaccinated humans. Peripheral blood was collected before, and 7, 14 and 28 days after vaccination. Four-colour flow cytometry was used for monitoring of vaccine induced T-cell response. In 15 donors, two- to fivefold increase in frequency of HA-specific T cells was observed 7 days after vaccination. In addition, in 12 of these donors, this increase was accompanied with fourfold increase of H1N1 antibody titre. The increase in frequency of HA-specific CD8+/IFN-gamma+ cells was low and peaked 28 days after vaccination in three of the six donors tested. Frequencies of HA-specific CD8+ T cells and antibody titre returned to prevaccination values 1 year after vaccination. Subunit influenza vaccines have the ability to induce HA-specific CD8+ cells. As the immune response to this vaccine decreased significantly after 1 year, our results confirm the importance of annual immunization for adequate protection.

Outcome of influenza vaccination in combat-related post-traumatic stress disorder (PTSD) patients.

Post-traumatic stress disorder (PTSD) is an anxiety disorder that can occur after exposure to extreme traumatic experience such as war trauma, and is accompanied by fear, helplessness or horror. Exposure to trauma can result in immune dysregulation and influence susceptibility to infectious disease as well as vaccine efficacy. The aim of the study was to determine the relation of psychological stress and the immune response to influenza vaccination in combat-related PTSD patients (n = 28). Detection of anti-viral antibody titre was performed by inhibition of haemagglutination assay. Ex vivo tetramer staining of CD8(+) T lymphocytes was used to monitor T cells specific for human leucocyte antigen (HLA)-A*0201-restricted influenza A haemagglutinin antigens before and after vaccination. Twenty patients showed a fourfold antibody titre increase to one or both influenza A viral strains, and 18 of them showed the same response for both influenza B viral strains. Ten of 15 healthy controls showed a fourfold rise in antibody titre to both influenza A viral strains and eight of them showed the same response for both influenza B viral strains. HLA-A*0201(+) PTSD patients (n = 10) showed a significant increase of influenza-specific CD8 T cells after vaccination. Although those PTSD patients had a lower number of influenza-specific CD8(+) T cells before vaccination compared to HLA-A*0201(+) healthy controls (n = 6), there was no difference in influenza A antibody titre between PTSD patients and control subjects before vaccination. The generated humoral and cellular immune response in PTSD patients argues against the hypothesis that combat-related PTSD in war veterans might affect protection following influenza vaccination.

Genetic characterization of wild type measles virus isolated in Croatia during the 2003-2004 outbreak.

Viral epidemiology is determined by the movement of infected people within and between geographical areas. The genetic characterization of wild-type isolates combined with standard epidemiological methods may enable the identification of the source and transmission pathways and permit differentiation between indigenous and imported viruses. We investigated the genetic characteristics of the wild-type measles virus isolated in Croatia during a 2003-2004 outbreak. The results of this study indicate the presence of the D4 measles virus genotype in Europe. The isolated virus is closely related to virus isolates from the India-like subgroup of the D4 measles virus genotype. The virus responsible for this outbreak differs in the hemagglutinin gene sequence from other virus strains belonging to the D4 genotype. The hemagglutinin gene sequence also differs when compared to viruses from other genotypes that are known to circulate in Europe and from vaccine strains.

Sudden deaths of Croatian hemodialysis patients in October 2001.

In 2001, there were 2,719 patients with chronic renal failure dialyzed in Croatia. Death rate in this patient group was 10.3%, similar to that in other countries. On October 12, 2001, the Croatian Institute of Public Health received information that four patients unexpectedly died in the dialysis center in Pozega General Hospital in a single day. Within a week, a total of 23 dialysis patients died in Croatia, of whom 5 during hemodialysis, and 18 within several hours after hemodialysis. Those events prompted us to assess the epidemiological situation in all hemodialysis centers in Croatia. We used phone contacts and reports of regional centers to collect the data. Clinical picture of the patients before death was characterized by dyspnea, hypotension, and cardiac arrest; resuscitation was unsuccessful in all cases. Analysis of all possible risk elements associated with hemodialysis revealed that dialysis devices, dialyzate, water, and personnel were different in all cases, and that the only common denominator in all events was dialyzer P-15 or P-18, manufactured by Baxter, USA, and distributed by Pliva, Croatia.

Decreasing risk of viral transfusion-transmitted diseases in Croatia.

AIM: To assess the risk of viral transfusion-transmitted infections in Croatia. METHODS: The following parameters were analyzed: frequency of blood donations repeatedly reactive for HBsAg and anti-HCV (1993-1999); blood donations confirmed positive for HBsAg and anti-HCV (1997-1999), anti-HIV1/2, and syphilis reactivity (1993-1999); number of registered patients with hepatitis B and C; transfusion-associated hepatitis B and hepatitis C; and frequency of HBV, HCV and HIV markers in patients with congenital bleeding disorders (1993-1998). RESULTS: The frequency of repeatedly reactive HBsAg and anti HCV markers and confirmed positive HBsAg, anti-HCV, and syphilis markers in donors blood decreased during the study, whereas the frequency of anti-HIV1/2 positivity did not change. The frequency of confirmed positive donors in 1999 was 0.068% for HBsAg, 0.035% for anti HCV, 0.002% for anti HIV1/2, and 0.0056% for syphilis. The number of patients with hepatitis B, hepatitis C, and transfusion-associated hepatitis B and C steadily decreased during the 1993-1998 period. The number of transfusion-associated hepatitis patients leveled off in 1997. From the beginning of the follow-up of AIDS patients in 1987, only 7 (2%) of hemophiliacs have been HIV-infected, all before 1990 and due to non-inactivated coagulation factor concentrates. There were no cases of transfusion-associated HIV2 infection in patients with congenital bleeding disorders or transfusion-associated HIV1 infection through transfusion of labile blood components. CONCLUSION: The safety of transfusion therapy in Croatia has improved, and the present risks of viral transfusion transmitted diseases are very low.

Pityriasis rosea Gibert: detection of Legionella micdadei antibodies in patients.

Some epidemiological and clinical characteristics of Pityriasis rosea Gibert has led us to hypothesize that this disease may be the clinical manifestation of an infection caused by legionellas. We have thus tested the sera of 36 patients ill with Pityriasis rosea and 19 controls for Legionella pneumophila serogroup 1-6 and Legionella micdadei antibodies. These, who had the same age and sex distribution as study patients, were receiving treatment for other diseases in the same ward. Also tested were 200 sera from the voluntary blood donors from the same region as study patients. Legionella micdadei antibodies were detected in 12 (33.3%) Pityriasis rosea cases and in one (5.2%) control. They were significantly more common in Pityriasis rosea cases than in either controls or voluntary blood donor population. The findings to date encourage continued research into the causative relationship between the Legionella micddadei infection and the onset of Pityriasis rosea Gibert.

[An epidemic of legionellosis at a hotel at the Makarska seashore]. / Epidemija legioneloze u hotelu na Makarskoj rivijeri.

The paper describes the epidemic of Legionellosis that occurred among guests and employees of a hotel at the Makarska littoral in May 1988. According to the so far reported data in the medical literature that was the third epidemic in our country and all three of them occurred in the Dalmatian touristic area. In this epidemic, nine foreign tourists were registered ill with the clinical picture of Legionnaires' disease. Five patients required hospitalization. The disease could be serologically proved in 4 patients and Legionella pneumophila SG1 was isolated from samples of 2 patients and from sediment of the hot-water tank. Since the opening of the hotel until the end of May, 19 hotel employees developed a febrile illness of short duration. The disease was serologically proved in 7 of them. The morbidity rate in tourists was 2.5%, while it amounted to 7.1% in the hotel employees. The epidemic lasted for 16 days. The infection spread through the hot water, and antiepidemic measures were limited to its pasteurization and hyperchloridation. The chain of infection was broken off by the application of those measures.

[An epidemic of legionnaires' disease in a hotel]. / Epidemija legionarske bolest u jednom hotelu.

An outbreak of legionnaires' disease and epidemic control measures taken at one of our hotels are described. Twenty (1% morbidity) hotel guests were affected with one dying. As a result of field investigations and survey the hot water supply system has been identified as the source of infection. Control measures which created conditions unfavourable to Legionella growth and replication in the hot water system stopped the outbreak.