Monthly Notifiable Disease Surveillance Report - Oct 2016

Brucellosis: One case of brucellosis (under investigation) was notified in October 2016. After further investigation, the case has since been found not to meet the case criteria.

Chikungunya fever: Three confirmed cases of chikungunya fever were notified in October. Twenty-six cases have been notified in the year to date compared to 48 at the same time in the previous year. Cases were in the 50–59 years (2 cases) and 20–29 years (1 case) age groups. Two cases reported overseas travel to India during the incubation period for the disease. The other case reported a prior history of overseas travel to Bali, Singapore and Viet Nam that might account for the infection.

Dengue fever: 10 cases of dengue fever (9 confirmed and 1 under investigation) were notified in October compared to seven cases notified in the same month of the previous year. All cases had travelled overseas during the incubation period for the disease. Countries visited included: Indonesia (5 cases), India (2 cases), Australia, Philippines, Thailand and Viet Nam (1 case each). One case reported travel to more than one country.

Diphtheria: One confirmed case of cutaneous diphtheria was notified in October 2016. The case was a male in the 40–49 years age group from Canterbury DHB. Overseas travel to Samoa during the incubation period for the disease was recorded.

Listeriosis: Two confirmed cases of non-perinatal listeriosis were notified in October. Cases were reported in the 30–39 years and 70 years and over age groups, and were from Auckland and Waikato DHBs, respectively. Risk factor information was recorded for both cases; one case was pregnant and the other case was overseas during the incubation period for the disease. The serotype was identified as L. monocytogenes serotype O1/2 and L. monocytogenes serotype O4 (1 case each).

Rheumatic fever: Eight cases of rheumatic fever - initial attack (4 confirmed, 3 probable and 1 suspect) and two cases of rheumatic fever – recurrent attack (1 confirmed and 1 probable) were notified in October 2016. This compares with nine cases (all initial attack) in the same month of the previous year. All cases were from the North Island: Auckland (3 cases), Counties Manukau and Waitemata (2 cases each), Northland, Bay of Plenty and Lakes (1 case each) DHBs. Cases ranged in age from 9 to 30 years, with the highest number of cases in the 20–29 years (4 cases) and 10–14 years (3 cases) age groups. Cases were reported in the Pacific peoples (6 cases), Māori (3 cases) and European or Other (1 case) ethnic groups. Nine cases were hospitalised. Numbers are based on report date which may not be a good indicator of newly incident cases as a high proportion of notifications have reporting delays.

Shigellosis: 15 cases of shigellosis (14 confirmed and 1 probable) were notified in October compared with ten cases notified during the same month of the previous year (Figure 1). The 12-month rate in October (3.2 cases per 100,000 population) was slightly higher than at the same time in the previous year (2.5 per 100,000). The highest number of cases was reported from Waitemata DHB (5 cases). The serotype involved was recorded for 73.3% (11/15) of cases: S. sonnei biotype g (6 cases), S. flexneri 1b and S. flexneri 6 (2 cases each) and S. flexneri (1 case). Information on overseas travel during the incubation period was recorded for 93.3% (14/15) of cases, of which 64.3% (9/14) of cases recorded overseas travel during the incubation period for the disease. Countries visited included: Samoa (4 cases), Tonga and Nepal (2 cases each), India, Mexico, Sri Lanka, United States of America and Viet Nam (1 case each). Three case reported overseas travel to more than one country. One case who did not travel during the incubation period for the disease reported a prior history of overseas travel to Bali that might account for the infection.

VTEC/STEC infection: 45 cases of VTEC/STEC infection (41 confirmed and 4 under investigation) were notified in October compared to 39 cases confirmed during the same month of the previous year. After further investigation, one case has since been found not to meet the case criteria. The 12-month rate in October (9.7 cases per 100,000) was notably higher than at the same time in the previous year (6.3 per 100,000). The highest number of cases was reported from Waitemata DHB (10 cases) followed by Counties Manukau DHB (7 cases). Cases ranged in age from 3 months to 93 years, with the highest number of cases in the 1–4 years age group (13 cases). Twelve cases were hospitalised. Thirty-eight cases have been confirmed by the Enteric Reference Laboratory as being infected with VTEC/STEC, and of these the serotype was identified as Escherichia coli O157:H7 (17 cases) and non-O157 (2 cases). Nineteen cases have verocytotoxin detected but a serotype has not yet been identified. Of the cases for which risk factor information was recorded, 82.6% (19/23) had contact with animals, 30.4% (7/23) had contact with a person with similar symptoms, and 25.0% (5/20) had contact with children in nappies during the incubation period for the disease. The increase in notifications for DHBs in the Auckland region may be due to a change in laboratory methods in July 2015; all faecal specimens are now screened for VTEC/STEC using PCR.

Yersiniosis: 115 cases of yersiniosis (108 confirmed and 7 under investigation) were notified in October 2016 compared to 68 cases notified in the same month of the previous year (Figure 2). After further investigation, five cases have since been found not to meet the case criteria. The highest numbers of cases were reported from Canterbury (26 cases), Auckland (12 cases) and Waikato (11 cases) DHBs. Cases ranged in age from 9 months to 85 years, with the highest number of cases in the 20–29 years age group (21 cases). Eleven cases were hospitalised. The Yersinia species involved was identified by ESR for 85.5% (94/110) cases; Y. enterocolitica (89 cases) and Y. pseudotuberculosis (5 cases). The most common Y. enterocolitica biotypes reported were biotype 1A (36 cases) and 2 (34 cases). Among the cases for which risk factor information was recorded, 43.1% (22/51) had consumed food from a food premises, 24.5% (13/53) had contact with other faecal matter or vomit, 20.0% (11/55) had recreational contact with water, and 19.0% (11/58) attended school, preschool or childcare during the incubation period for the disease.

Zika virus infection: Two cases of zika virus infection (1 probable and 1 under investigation) were notified in October 2016. After further investigation, one case has since been found not to meet the case criteria. The case was a female in the 20–29 years age group, of European or Other ethnicity and from Capital & Coast DHB. Overseas travel to Tonga during the incubation period for the disease was recorded.