A Tularemia Outbreak of Historical Proportions in the Norrbotten County, Sweden (nr. 1434) Tomas N Gustafsson, MD, PhD (1,2)*, Anders Nystedt, MD (1,3) (1)Infectious Disease Clinic, Sunderby Hospital, Luleå, Sweden, (2) Department of Clinical Microbiology, Umeå University, Umeå, Sweden, (3) Unit for Disease Prevention and Control, Sunderby Hospital, Luleå, Sweden (*)Presenting and corresponding author ([email protected])

Introduction Results Distribution of clinical forms – the ulceroglandular form was predominant Tularemia, which is caused by the bacterium Francisella tularensis, exist in The largest outbreak in the Norrbotten County. several different forms; ulceroglandular, occuloglandular, typhoid (septic), r 450 pulmonary and oropharyngeal. Sweden experiences recurrent outbreaks with a 3 Oropharyngeal e The incidence varies widely As expected, the y 400 irregular intervals and geographical localizations. Although infections with 32 Pulmonary r between years as illustrated e 350 47 Typhoid ulceroglandular form the type B strains found in Sweden does not normally result in fatalaties, they p 300 for the last 20 years. The 406 324 Ulceroglandular dominted with almost 80% s cause significant morbidity unless treated early. Infections are normally e cases of 2015 is a doubling of s 250 of reported cases. There

treated with ciprofloxacin or doxycycline although aminoglycosides can be a c 200 the previous high in the year were no reported used. The infection is classified as notifiable under the Swedish f o of 2012 and puts it amongst 150 occuloglandular cases. Communicable Diseases Act. r e 100 the largest outbreaks in b The Norrbotten County is the largest and northernmost county in Sweden m 50 Sweden during the period for u and is situated around the arctic circle. It comprises 14 municipalities with a N 0 which statistics is available. 2000 2005 2010 2015 total area of 98 911 km2, which is about 25% of the total land area in Sweden. Age distribution – the typical patient was middle-aged The county has about 250 000 inhabitants which is 2.5% of the total Timeline – a peak in mid August with a tail well past Age distribution population in Sweden and has a population density close to that of Montana. the end of mosquito season Cases were grouped according 80 Almost 60% of the population live in the 3 municipalities Luleå (75966 to age in intervalls of 10 years.

The first case was s inhabitants) , Piteå (41508 inhabitants) and Boden (27887 inhabitants). 25 e 60 Most cases were diagnosed in s

reported in late July a

c

people aged 40-69. This f o and by the first days of Starting in July 2015, we experienced an unusually large outbreak of 40 20 probably corresponds to the r August, it was apparent e

tularemia, promting an epidemiological investigation. b year

peak in activities such as m

the outbreak would be u 20 N

per per fishing, hunting and foraging substantial. The 15 which results in exposure to outbreak peaked in mid 0 9 9 9 9 9 9 9 9 9 9 cases mosquitoes. - 1 2 3 4 5 6 7 8 9 0 ------August, but sporadic 0 0 0 0 0 0 0 0 0 10 1 2 3 4 5 6 7 8 9 cases were reported of Kiruna Age group (years) during several months 5 afterwards. Mosquito Numer Actions taken during the outbreak season is largely over by Gällivare Pajala the end of August. • Updated guidelines for diagnosis and treatment. Arctic circle l u g p v c J u e o e - -A -S -N -D • Frequent updates of statistics (multiple times per week) 1 5 9 3 8 2 2 2 Jokkmokk during the outbreak. Övertorneå Geographic distribution – the majority of cases in • Educational efforts (media, e-mails to physicians, hospital Arjeplog Överkalix municipalities close to the coast homepage etc).

) 400 Haparanda .

Boden h n

i Conclusions

Kalix 0

0 300

Älvsbyn Luleå 0

Arvidsjaur • The tularemia outbreak of 2015 was the largest in

0

0 1 200

Piteå / Norrbotten so far and one of the largest ever in Sweden.

(

e Kiruna

c • Outbreaks seems to become more common and result in

n 100 13 e

d more cases in Norrbotten.

i

c n I 0 • The 2015 outbreak showed expected patterns of age- Methods Gällivare Pajala g r n e a k x a å a å n x å y o u e r d k li n e l e y li e t l a a a l ja t b a n distribution and clinical manifestations. Cases were extracted from the County p j d v n o ru u a i rn u 2 2 e s o li ra m K i L P s rk o o j id B l a k K P lv e t r v ä k Ä v r C A r G p o e Council of Norrbottens database for A a J Ö v Jokkmokk H Ö Övertorneå notifiable diseases and were analyzed with 4 Överkalix 0 Contact information Funding respect to geographic localization, clinical Cases were reported from all municipalities accept for one. Arjeplog 1 Dr. Tomas N Gustafsson • The County Counsel of presentation and a number of other 1 Haparanda Boden The highest incidence was 3 Infectious Disease Clinic Norrbotten. parameters. Population figures and maps 93 Kalix found in Boden with 330 cases 6 Sunderby Hospital • Umeå University (ALF) were obtained from Statistics Sweden Älvsbyn Luleå (www.scb.se) /100 000 inhabitants. Absolute Arvidsjaur 10 221 SE-971 80, Luleå, Sweden • The Swedish Society of 2 number of cases are given in Piteå [email protected] Medicine bold in the figure on the right. 48 Tel: +46701700504