Monthly Notifiable Disease Surveillance Report - Mar 2016

Cholera: One case of cholera was notified in March 2016. The case was a male in the 70 years and over age group from Waikato DHB. After further investigation, the case has since been found not to meet the case criteria.

Cryptosporidiosis: 51 cases of cryptosporidiosis (49 confirmed and 2 under investigation) were notified in March 2016 compared to 23 cases notified during the same month of the previous year. The 12-month rate in March (16.4 cases per 100,000) was higher than at the same time in the previous year (12.8 per 100,000). The highest numbers of cases were reported from Auckland (11 cases), Waitemata (9 cases), Canterbury and Southern (6 cases each) DHBs. The cases ranged in age from 16 months to 88 years, with the highest numbers of cases in the 1–4 years (12 cases) and 40–49 years (8 cases) age groups. Among the cases for which risk factor information was recorded, 53.3% (8/15) had recreational water contact, 41.7% (5/12) had consumed food from a food premises, 33.3% (4/12) had contact with farm animals, and 25.0% (3/12) had consumed untreated water during the incubation period. One finalised Cryptosporidium outbreak was created in March (2 cases).

Hepatitis NOS: One confirmed case of hepatitis NOS (hepatitis epsilon) was notified in March. The case was a male in the 20–29 years age group from Auckland DHB. The case was recorded as being overseas during the incubation period for the disease.

Legionellosis:22 cases of legionellosis (13 confirmed, 4 probable and 5 under investigation) were notified in March 2016 compared to 20 cases notified during the previous month, and 10 during the same month of the previous year. The 12-month rate in March (6.5 cases per 100,000) was notably higher than at the same time in the previous year (2.9 per 100,000). Cases were reported from Northland (5 cases), Counties Manukau, Capital & Coast, Canterbury (3 cases each), Waikato, Bay of Plenty, Auckland (2 cases each), Waitemata and Southern (1 case each) DHBs. The Legionella species was identified for 12 cases as: L. longbeachae (7 cases), L. pneumophila (3 cases), L. bozemanae and L. jordanis (1 case each). The increase in legionellosis notifications compared to the same time in the previous year may be due to the LegiNZ study, which began in May 2015 and involves 20 hospitals in 17 DHBs.

Leptospirosis: Seven cases of leptospirosis (5 confirmed and 2 under investigation) were notified in March compared to ten cases notified during the same month of the previous year (Figure 1). After further investigation, one case has since been found not to meet the case criteria. Cases were reported from Hawke’s Bay (2 cases), Counties Manukau, Waikato, Wairarapa and Whanganui (1 case each) DHBs. The highest number of cases was in the 20–29 years age group (5 cases). Occupational exposure risk factor information was recorded for 83.3% (5/6) of cases, three worked in the meat processing industry and two were farmers or farm workers. The case that did not have occupational risk factor information recorded had travelled to Bali during the incubation period for the disease. The Leptospira species was recorded for three cases; L. Hardjo (2 cases) and L. Tarassovi (1 case).

Listeriosis: Seven cases of listeriosis (6 confirmed non-perinatal and 1 perinatal under investigation) were notified in March 2016 compared to two cases (both non-perinatal) in the same month of the previous year. The mother in the perinatal case was in the 30–39 years age group, was of Pacific peoples ethnicity and was from Auckland DHB. The infant survived after delivery at 32 weeks gestation. The non-perinatal cases were in the 60–69 years and 70 years and over (2 cases each), 20–29 years and 50–59 years (1 case each) age groups. The serotype of all non-perinatal cases was confirmed: Listeria monocytogenes serotype O1/2 (4 cases) and Listeria monocytogenes serotype O4 (2 cases).

Measles: Six cases of measles were notified in March 2016 compared to two cases notified during the same month of the previous year. After further investigation, all cases have since been found not to meet the case criteria.

Pertussis: 82 cases of pertussis (33 confirmed, 44 probable and 5 under investigation) were notified in March 2016 compared to 77 cases in 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 March (27.3 cases per 100,000) was higher than at the same time in the previous year (21.3 per 100,000). Six cases were hospitalised and no deaths were reported. Forty-two percent (34/81) of cases were laboratory-confirmed (7 by culture, 24 by PCR, and 3 by culture and PCR). The highest numbers of cases were reported from Canterbury (17 cases), Waitemata and Waikato (12 cases each) and Capital & Coast (9 cases) DHBs. The cases ranged in age from 1 month to 82 years, with 19.8% (16/81) under 5 years of age (including 4 cases aged less than 1 year). The highest numbers of cases were in the 40–49 years (14 cases), 1–4 years (12 cases) and 50–59 years (10 cases) age groups. One finalised B. pertussis outbreak was created in March (2 cases).

Salmonellosis: 101 cases of salmonellosis (100 confirmed and 1 under investigation) were notified in March 2016 compared to 103 cases notified during the same month of the previous year (Figure 2). The highest numbers of cases were reported from Canterbury (14 cases), Auckland and Waikato (11 cases each), and Tairawhiti (10 cases) DHBs. The cases ranged in age from 2 months to 80 years, with the highest numbers of cases in the 1–4 years (21 cases), 50–59 years (14 cases), and 30–39 years (13 cases) age groups. Fifteen cases were hospitalised. The Salmonella serotypes were identified in 96/101 (95.0%) of the cases, the most common were S. Stanley (9 cases) and S. Enteritidis phage type 11 (8 cases). Uncommon Salmonella serotypes confirmed this month included S. Enteritidis phage type 7, S. Enteritidis phage type 26 variant, S. Haifa, S. Kiambu, S. Sandiego and S. Victoria (1 case each). Among the cases for which risk factor information was recorded, 56.8% (21/37) had consumed food from a food premises, 27.3% (12/36) had contact with farm animals, 20.5% (8/39) had recreational contact with water, 15.1% (8/53) had travelled overseas, and 13.5% (5/37) had contact with other symptomatic people during the incubation period for the disease. One finalised Salmonella outbreak was created in March (2 cases).

VTEC/STEC infection: 69 cases of VTEC/STEC infection (57 confirmed and 12 under investigation) were notified in March compared to 40 cases confirmed during the same month of the previous year. After further investigation, four cases have since been found not to meet the case criteria. The 12-month rate in March (9.4 cases per 100,000) was notably higher than at the same time in the previous year (4.8 per 100,000). The highest numbers of cases were reported from Waitemata (15 cases), Counties Manukau (14 cases), Waikato (10 cases) and Northland (9 cases) DHBs. The highest numbers of cases occurred in the 1–4 years (13 cases), 20–29 years (12 cases), 70 years and over (8 cases) and 60–69 years (7 cases) age groups. Fourteen cases were hospitalised. Fifty-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 (36 cases) and non-O157 (22 cases). Of the cases for which risk factor information was recorded, 60.0% (15/25) had contact with animals, 37.5% (9/24) had recreational contact with water, 33.3% (7/21) had contact with children in nappies, 14.3% (4/28) had travelled overseas, and 8.3% (2/24) had contact with a person with similar symptoms 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. Two interim VTEC/STEC outbreaks were created in March (case numbers yet to be determined).

Zika virus infection: 11 cases of zika virus infection (7 confirmed, 3 probable and 1 under investigation) were notified in March 2016. After further investigation, one case has since been found not to meet the case criteria. The highest number of cases was reported in the 20–29 years and 50–59 years age groups (3 cases each). Laboratory testing information was recorded for all cases, of which 70.0% (7/10) of cases were confirmed by PCR. All cases travelled during the incubation period for the disease, and countries visited included Tonga (6 cases), Samoa (3 cases), and Papua New Guinea (1 case, who had also been in transit in Australia).