Giardiasis - Annual Epidemiological Report for 2014

Key facts

• In 2014, 17 278 confirmed giardiasis cases were reported in the EU/EEA.
• The notification rate was 5.4 confirmed cases per 100 000 population.
• The highest notification rate was observed in the age group 0–4 (16.2 for males and 8.6 for females).
• The trend for 2010–2014 remained relatively stable.

Methods

Click here for a detailed description of the methods used to produce this annual report

• In 2014, 23 countries reported giardiasis cases in the EU/EEA in 2014. None of these reported zero cases.
• The EU case definitions of 2012/2008 were used by 19 of the 23 countries (Annex).
• Two of the reporting countries had active surveillance of giardiasis (Annex).
• Notification rates and age-standardised rates were not calculated for Belgium, Spain and Romania because the respective national surveillance systems are sentinel systems and do not cover the whole population.
• Although Poland provided aggregated seasonality data for the 2014 cases, data were missing for 2010–2013. Poland could therefore not be included in the seasonal trend analysis.

Epidemiology

In 2014, 17 278 confirmed giardiasis cases were reported by 23 countries in the EU/EEA (Table 1). The highest number of cases was reported by Germany (N=4 011), followed by the United Kingdom (N=3 628) which accounted for 44% of cases (Figure 1). In 2014, slight increases compared with 2013 were reported by several countries, while case-numbers doubled in Romania and Latvia.

Notification rate

The notification rate reported for confirmed giardiasis in the EU/EAA in 2014 was 5.4 cases per 100 000 population (Figure 2). The highest notification rates were reported by Bulgaria (23.9), Estonia (16.8) and Sweden (13.1).

Age and gender distribution

For cases with available gender data (84% of confirmed cases), the notification rate in males was 6.1 per 100 000 population and in females 4.6 per 100 000. The highest notification rate was observed in the age group 0–4 years, with 16.2 cases per 100 000 for males and 8.6 cases per 100 000 for females (Figure 3).

In the age group 0–4 years, the highest notification rates were reported by Bulgaria (195.3), Estonia (120.8) and Sweden (42.3).

Seasonal distribution

Data on seasonality were reported by 18 of the 23 countries (Figure 4). Similarly to previous years, the cases peaked in September and October.

Multiannual trend

The number of reported giardiasis cases remained relatively stable during the period between 2010 and 2014 (Table 1, Figure 5). Thus, 12-month averages do not show any significant trend (Figure 5).

Threats description for 2014

No public health threats related to giardiasis were reported to, or detected by, ECDC in 2014.

Discussion

Giardiasis is a common parasitic infection worldwide, caused by the protozoan Giardia lamblia (syn. G. duodenalis, G. intestinalis) [1]. The disease may be asymptomatic and selflimiting or characterised by fatigue, bloating, acute diarrhoea and other chronic gastrointestinal symptoms [2]. Infection occurs frequently via ingestion of contaminated food or water (recreational waters, swimming pools or drinking water) but person-to-person transmission may also occur, e.g. through sexual transmission [3-5].

The giardiasis multiannual trend in the EU/EEA is stable, but notification rates remain high, especially in eastern and southern Europe. Considering the likely degree of underreporting and under-ascertainment, this is of public health concern because of drug resistance [6] and potentially increasingly favourable climatic conditions due to climate change [7].

Public health conclusions

Giardiasis remains a common parasitic disease in the EU/EEA. There is a need to better understand the epidemiology of this disease, increase awareness among clinicians and implement prevention programmes tailored to the national epidemiological situation. In addition, diagnostic algorithms and methods and their use in Europe should be reviewed and assessed because of recent advances in giardiasis diagnostics. The respective case definitions for data reporting should be updated accordingly to allow for better collection of data, which could then inform public health decisions.

References

1. Cama VA, Mathison BA. Infections by Intestinal Coccidia and Giardia duodenalis. Clin Lab Med. 2015 Jun;35(2):423-44.
2. Halliez MC, Buret AG. Extra-intestinal and long-term consequences of Giardia duodenalis infections. World J Gastroenterol. 2013 Dec 21;19(47):8974-85.
3. Escobedo AA, Almirall P, Alfonso M, Cimerman S, Chacín-Bonilla L. Sexual transmission of giardiasis: a neglected route of spread? Acta Trop. 2014 Apr;132:106-11.
4. Alexander C, Jones B, Inverarity D, Pollock KG. Genotyping of Giardia isolates in Scotland: a descriptive epidemiological study. Epidemiol Infect. 2014 Aug;142(8):1636-9.
5. Altzibar JM, Zigorraga C, Rodriguez R, Leturia N, Garmendia A, Rodriguez A. Outbreak of acute gastroenteritis caused by contamination of drinking water in a factory, the Basque Country. J Water Health. 2015 Mar;13(1):168-73.
6. Leitsch D. Drug resistance in the microaerophilic parasite Giardia lamblia. Curr Trop Med Rep. 2015;2(3):128-135.
7. Lal A, Baker MG, Hales S, French NP. Potential effects of global environmental changes on cryptosporidiosis and giardiasis transmission. Trends Parasitol. 2013 Feb;29(2):83-90