Chikungunya virus (CHIKV) seroprevalence in the South Pacific populations of the Cook Islands and Vanuatu with associated environmental and social factors

BACKGROUND

Arthropod-borne diseases pose a significant and increasing risk to global health. Given its rapid dissemination, causing large-scale outbreaks with severe human infections and economic loss, the Chikungunya virus (CHIKV) is one of the most important arboviruses worldwide. Despite its significance, the real global impact of CHIKV remains underestimated as outbreak data are often incomplete and based solely on syndromic surveillance. During 2011-2016, the South Pacific Region was severely affected by several CHIKV-epidemics, yet the area is still underrepresented in arboviral research.

METHODS

465 outpatient serum samples collected between 08/2016 and 04/2017 on three islands of the island states Vanuatu (Espiritu Santo) and the Cook Islands (Rarotonga, Aitutaki) were tested for anti-CHIKV specific antibodies using Enzyme-linked immunosorbent Assays.

RESULTS

A total of 30% (Cook Islands) and 8% (Vanuatu) of specimens were found positive for anti-CHIKV specific antibodies with major variations in national and intranational immunity levels. Seroprevalence throughout all age groups was relatively constant. Four potential outbreak-protective factors were identified by comparing the different study settings: presence of Ae. albopictus (in absence of ECSA E1-A226V-mutation CHIKV), as well as low levels of human population densities, residents' travel activity and tourism.

CONCLUSION

This is the first seroprevalence study focussing on an arboviral disease in the Cook Islands and Vanuatu. It highlights the impact of the 2014/2015 CHIKV epidemic on the Cook Islands population and shows that a notable part of the Vanuatu test population was exposed to CHIKV although no outbreaks were reported. Our findings supplement the knowledge concerning CHIKV epidemics in the South Pacific Region and contribute to a better understanding of virus dissemination, including outbreak modifying factors. This study may support preventive and rapid response measures in affected areas, travel-related risk assessment and infection identification in returning travellers.

TRIAL REGISTRATION

ClinicalTrials.gov Aachen: 051/16_09/05/2016 Cook Islands Ref.: #16-16 Vanuatu Ref.: MOH/DG 10/1/1-GKT/lr.

Mycoplasma hominis and Ureaplasma urealyticum in patients with sterile pyuria

OBJECTIVES

Mycoplasma hominis and Ureaplasma urealyticum are associated with various diseases of the urogenital tract, but they are usually not detected by routine microbiological diagnosis. The aim of this study was to asses the prevalence of these organisms in patients with sterile pyuria.

METHODS

From December 2000 to June 2001 all urine samples sent in to microbiological diagnosis, which yielded > or =500 leucocytes/ml and <10(4) bacteria/ml, were collected for this study. Thirty-three samples from 30 patients (female: 21, male: nine; median age: 60 years, range: 23-91 years) met these criteria and were subjected to PCR for detection of M. hominis and U. urealyticum, respectively.

RESULTS

M. hominis and U. urealyticum were detected in 2 (7%) and 6 samples (20%), respectively. With regard to the underlying diseases of the patients, glomerulonephritis was significantly associated with the detection of urogenital mycoplasmas (p=0.02).

CONCLUSION

The prevalence of M. hominis and U. urealyticum found in this study corresponds to the expected prevalence in the general population. This finding does not indicate an association of sterile pyuria with urogenital mycoplasma infection/colonization.

Bacteremia with Mycoplasma hominis and Ureaplasma urealyticum in Patients Undergoing Hysterectomy

In the study presented here, the aim was to investigate the frequency and clinical significance of bacteremia with urogenital mycoplasmas in immunocompetent patients following gynecological surgery. Among 56 patients undergoing elective hysterectomy (mean age, 55 years; range, 32-82 years), Mycoplasma hominis and Ureaplasma urealyticum were detected in urine by PCR in 2 and 11 patients, respectively. Pre- and postoperative blood samples of the colonized patients were investigated for the colonizing species by PCR. In 4 of the 11 patients colonized by Ureaplasma urealyticum the pathogen was also detected from one of the postoperative blood samples, while no case of bacteremia with Mycoplasma hominis was detected. The postoperative course was uncomplicated in all patients.