Malaria

General Information

Malaria is an infectious disease, caused by the parasite “plasmodium” of malaria and is transmitted through the bite of infected mosquitoes of the “Anopheles” genus. Mosquitoes are infected from infectious patients (i.e., patients with parasitemia).

Ongoing transmission of malaria is currently recorded in 85 countries/ areas around the world (WHO, World Malaria Report, 2023), mainly in sub-Saharan Africa, Asia and Latin America. Until the mid-twentieth century, several countries in Europe and North America were also malaria endemic, but -after intense malaria control programs- it was eliminated.

Malaria was eliminated from Greece in 1974, following an intense control program (1946- 1960). Since then, several (20-110 cases) imported cases are recorded annually, referring to patients infected abroad. Increased numbers of imported malaria cases are expected due to the increase of travels and population movements worldwide, and are observed in all developed countries.

Additionally, during the period 2009 – 2021, a number of locally acquired/introduced P. vivax malaria cases were recorded in some -mainly rural- areas of the country (i.e., among patients without travel history to a malaria endemic country), mainly as sporadic introduced cases (1^st generation transmission) but also in clusters (in 2011 – 2012).

The following Table presents the number of malaria cases reported to the Hellenic National Public Health Organization (NPHO) by year of symptom onset (for imported cases) or infection (for locally acquired cases) and by epidemiological case classification (imported/ locally acquired), in 2009-2023.

Table 1: Reported malaria cases by year of symptom onset¹ (for imported cases) or infection (for locally acquired/ introduced cases) and by epidemiological case classification (imported/ locally acquired), Greece, 2009 – 2023².

Year	Case classification
Year	Imported cases	Locally acquired/ introduced cases³
2009	44	7
2010	40	4
2011	54	42
2012	73	20
2013	22	3
2014	38	0
2015	79	8
2016	111	6
2017	100	7
2018	44	11
2019	38	1
2020	21	2
2021	28	4
2022	31	0
2023	32	0

Cases with no information regarding symptom onset were classified according to the year of hospitalization or notification to the NPHO.
Known reported relapses, two locally acquired malariae cases (2012), that were attributed to former transmission periods, and three malaria cases “of undetermined classification” (two in 2016 and one in 2018) are not included.
All were vivax cases, except five hospital-acquired P.falciparum cases (one in 2017, one in 2020 and a cluster of three cases in 2021, all included in the Table).

As indicated by the malaria surveillance data of the last years, in the malaria-free Greece, the risk of re-introduction of the disease in specific vulnerable and receptive areas of the country exists, especially where the presence of adequate numbers of Anopheles mosquitoes (the competent vector of the disease) is combined with the presence of malaria patients coming from endemic countries.

Following a peak of locally acquired P.vivax malaria cases in 2011-2012, their number declined steadily in the following years, with recording of only a limited number of sporadic introduced cases (1^st generation of transmission), in few vulnerable and receptive rural areas (mosquito-borne P.vivax transmission, through mosquitoes infected from imported cases from malaria endemic countries). This decrease is the result of a number of intense public health interventions uninterruptedly implemented since 2011, with the collaboration of various stakeholders at the national, regional and local level, which have contributed to the successful prevention of the re-appearance of malaria in Greece. In the last two years (2022-2023) no locally acquired malaria cases were recorded in Greece.

Early detection and eradication treatment of malaria cases, personal protection against mosquito bites and the timely implementation of effective integrated vector control measures represent the main components of the public health strategy to prevent P.vivax reintroduction and re-appearance in high risk areas of the country.

The Hellenic National Public Health Organization has developed (since 2011) and continuously implements an operational action plan for the management of malaria. In addition, in 2015, the Ministry of Health published the “National Action Plan for the Management of Malaria”. According to these plans, a series of activities are implemented nationwide for the prevention and management of malaria, with the collaboration of national, regional and local authorities, which include: risk assessment, enhancement of malaria surveillance and laboratory malaria diagnosis, proper case management, communication activities for the public, health professionals and local authorities, mosquito vector surveillance and control activities, and blood safety measures.

More detailed information regarding malaria surveillance data and activities for the prevention of malaria in Greece can be found in the published ad hoc and annual malaria surveillance reports.

HCDCP

Malaria

General Information

Epidemiological Surveillance