Rickettsiae and rickettsial diseases in Croatia: Implications for travel medicine

AIM

To review the current state of knowledge concerning rickettsiae and rickettsioses in Croatia and to discuss their implications for travellers.

METHODS

The PubMed database was searched from 1991 to 2015 by combining the words "rickettsia," "rickettsiosis", "travellers" and "Croatia".

RESULTS

Since 1969, Croatia appears to be free of epidemic typhus (ET) caused by Rickettsia prowazekii and the last case of Brill-Zinsser disease was recorded in 2008. Mediterranean spotted fever (MSF) caused by Rickettsia conorii is the most frequent human rickettsial infection in Croatia, followed by murine typhus caused by Rickettsia typhi. Human cases of MSF and murine typhus have been predominantly observed along the eastern Adriatic coast from Zadar to Dubrovnik and between Zadar and Split, respectively. Rickettsia akari, etiologic agent of rickettsialpox, was isolated from blood of a patient diagnosed with MSF in Zadar, but no cases of rickettsialpox were reported. Several species of pathogenic (Rickettsia slovaca, Rickettsia aeschlimannii, Ricketsia helvetica, and Ricketsia raoultii) and species of undetermined pathogenicity (Ricketsia hoogstraalii sp. nov.) rickettsiae were identified in ticks collected in different ecological regions of Croatia. A search of the literature revealed no evidence of rickettsial infection in travellers visiting Croatia. Three imported cases of Rickettsia africae were observed in travellers returning from South Africa.

CONCLUSION

Rickettsiae and rickettsial diseases continue to be present in Croatia. As they can be acquired while travelling, physicians should consider rickettsial infection in the differential diagnosis of patients returning from Croatia and presenting with febrile illness.

Seroprevalence and entomological study on Chikungunya virus at the Croatian littoral

During 2011-2012, a total of 1008 serum samples from randomly selected inhabitants of seven Croatian counties located on the Adriatic Coast were tested for the presence of chikungunya virus (CHIKV) IgG antibodies using indirect immunofluorescence assay. Nine participants (0.9%) from four counties were found to be seropositive to CHIKV. Seroprevalence varied from 0.5% to 1.8% between counties. Additionally, a total of 3,699 mosquitoes were captured in 126 localities from August 16 to September 24, 2011. Three mosquito species were found: Ae. albopictus (3010/81.4%), Cx. pipiens (688/18.6%) and only one specimen of the Cs. longiareolata. Female mosquitoes (N = 1,748) were pooled. All pools tested negative for CHIKV RNA using a real-time RT-PCR.

Dengue virus infection in Croatia: seroprevalence and entomological study

During 2011-2012, a total of 1,180 sera samples were collected from residents of seven Croatian counties located on the Adriatic Coast and four counties in northeastern Croatia and tested for the presence of dengue virus (DENV) IgG antibodies using ELISA. Reactive samples were further tested by IFA. Seven samples (0.59%) tested positive for DENV antibodies. Seroprevalence rates by county varied from 0-2.21%. The highest seropositivity rate (2.21%) was found in the Dubrovnik-Neretva County where autochthonous dengue cases were recorded in 2010. Additionally,3,699 mosquitoes were collected from 126 localities along the Adriatic coast in August-September, 2011. Aedes albopictus was the most prevalent species (81.37%). No evidence of DENV RNA was detected by RT-PCR among 1,748 female mosquitoes.

Latrodectus bites in northern Dalmatia, Croatia: clinical, laboratory, epidemiological, and therapeutical aspects

AIM

To analyze clinical and epidemiological characteristics of the black widow spider (Latrodectus tredecimguttatus) bites and asses the impact of antitoxin administration after the bite on the intensity and duration of pain.

METHOD

Retrospective analysis of clinical appearance, laboratory findings, and clinical assessment of the antitoxin administration efficacy in 32 patients with latrodectism treated at Zadar General Hospital between 1992 and 2002.

RESULTS

All patients presented with generalized pain, profound perspiration, and burning in the sole of the foot. Laboratory findings revealed moderately increased serum glucose concentrations in half of the patients, concentrations of aspartate aminotransferase and alanine aminotransferase 2 to 3 times higher than normal in 8 of 32 patients, moderate leukocytosis in 16 of 32 patients, mature neutrophilia in 15 of 32 patients, and immature forms of leukocytes in 4 of 32 patients. In 21 patients who received the antitoxin, severe pain lasted 1-4 h (median, 1.2 h) after the antitoxin administration, moderate pain 1-5 h (median, 2.4 h), and hospitalization 1-5 days (median, 4 days). In patients who did not receive antitoxin, there was a statistically significant increase in duration of severe pain (median, 50 h; range, 24-72 h), moderate pain (median, 36 h; range, 24-48 h), and hospitalization (median, 6 days; range, 4-12 days) (p<0.05 for all, Kruskal-Wallis H test). Men were more often bitten by the venomous spider (20 men vs 12 women); adults more often than children (30 vs 2, respectively), domestic population more often than tourists (30 vs 2, respectively), and rural mainland inhabitants more often than islanders (21 vs 11, respectively). All biting incidents occurred between June and September, most often in July (17 patients).

CONCLUSION

Latrodectism in Northern Dalmatia presents with severe clinical symptoms. Administration of the antitoxin is advisable in the treatment of all afflicted patients.