PAHO

Following a continued decrease in the number of malaria cases from 2005 to 2014 in the Region of the Americas, an increase was observed in 2015, 2016, and most recently in 2017. In 2016, 9 countries of the Region (Colombia, Ecuador, El Salvador, Guyana, Haiti, Honduras, Nicaragua, Panama, and the Bolivarian Republic of Venezuela) reported an increase in malaria cases.

In 2017, five countries reported an increase in malaria cases: Brazil, Ecuador, Mexico, Nicaragua, and Venezuela. In addition, Cuba and Costa Rica reported indigenous cases and Honduras reported malaria cases in an area where cases had not been detected recently. Following are summaries of the malaria situation in several countries of the Region.

In Brazil, the International Health Regulations (IHR) National Focal Point reported that between January and November of 2017, there were 174,522 malaria cases reported in the Amazon region, representing an increase in comparison to the same period of 2016 when 117,832 malaria cases were reported. In 2017, the same states, with the exception of Mato Grosso, presented an increase compared to 2016 (Table 1). The states reporting the most cases were Amazonas, Pará, and Acre. In 2017, 10% (17,411 cases) of the reported malaria cases in the Amazon region, correspond to malaria due to P. falciparum and mixed infections, representing a total higher than that reported for the same period in 2015 (14,084) and in 2016 (12,366).

In Costa Rica, the Ministry of Health reported 12 indigenous cases of malaria in 2017, in the cantons of San Carlos (6 cases), Matina (3 cases), and Sarapiqui (3 cases). This represents an increase compared to 2016 when 4 indigenous cases were notified.1,2 The detection of cases in these localities highlights the risk of re-establishment of transmission in areas where ecological conditions persist.

In Ecuador, between epidemiological week (EW) 1 and EW 52 of 2017, a total of 1,279 malaria cases were reported, of these 72% correspond to P. vivax and 28% to P. falciparum.3 The number of cases reported in 2017 is higher than that reported in 2016 (926).4 The four provinces with the highest number of cases in 2017 were Morona Santiago (489), followed by Orellana (240), Pastaza (223), and Esmeraldas (215).

In Honduras, the IHR National Focal Point reported the first indigenous cases of P. vivax malaria on 30 August 2017 in the village of La Charamusca, municipality of Esquías, department of Comayagua. A total of 34 confirmed cases were reported with date of onset of symptoms between EW 27 and 37 of 2017. During the outbreak investigation, the presence of Anopheles pseudopunctipennis was reported as a vector that could be involved in the transmission. The low number of cases registered in the department of Comayagua in the last five years and the absence of transmission for several years in the affected locality, highlights the importance of maintaining surveillance and response capabilities in areas where transmission has been interrupted.

In Mexico, the Secretariat of Health notified 704 malaria cases between EW 1 to EW 50 of 2017, representing an increase from the 514 cases reported in the same period of 2016.5 The increase was particularly notable in the states of Chiapas, Chihuahua, and Tabasco, and highlighted are cases in territories without recent transmission (San Luis Potosí).

In Nicaragua, between EW 1 and EW 52 of 2017, there were 10,846 malaria cases reported, representing an increase compared to the same period in 2016 when 6,209 cases were reported.6 The majority of the cases have been reported from the North Caribbean Coast Autonomous Region.7

The Venezuela, IHR National Focal Point notified the Pan American Health Organization, Regional Office of the World Health Organization (PAHO/WHO), on 27 November 2017, that between EW 1 and EW 42 of 2017 there were 319,765 malaria cases reported between EW and EW 42 of 2017 (Figure 1); representing an increase in comparison to the accumulated reported cases in 2016 (240,613).8

Of the cases reported in 2017, 77% were due to P. vivax, 17% due to P. falciparum, 6% due to mixed infections, and <1% due to P. malariae.

The number of malaria cases reported in 2017 was higher than the annual average recorded in the past 29 years (1988-2016).9

The three states with the highest number of confirmed cases during 2017 were Bolívar (205,215), followed by Amazonas (52,471) and Sucre (45,622). The majority of municipalities in these three states are characterized as having very high and high risk of malaria transmission according to the annual parasitic incidence (API). The risk of malaria is highest in those of 20 to 39 years and account for nearly half of all the cases (47%), showing the risk related to economic activities. Of the total confirmed cases, 64% (203,956) are male and across all age groups more cases in males were reported than in females