Clinical and epidemiological aspects of complicated malaria in Colombia, 2007-2013

Abstract

Background: During the last decade, Colombia presented a significant decrease in malaria clinical cases and associated mortality. However, there is a lack of reliable information about the prevalence and characteristics of complicated malaria cases as well as its association with different Plasmodium species. A description of the epidemiological and clinical aspects of complicated malaria in Colombia is presented here.

Methods: A descriptive study was conducted using data collected between 2007 and 2013 by the Public Health Surveillance System (SIVIGILA). Demographic and clinical features were described. Frequency of complicated malaria cases, annual parasite index (API) and annual percent change (APC) for trend modelling by gender and age were also calculated.

Results: A total of 547,542 malaria cases were recorded by SIVIGILA during the study period, of which 2553 (0.47 %) corresponded to complicated cases with similar distribution by Plasmodium vivax and Plasmodium falciparum species. Mixed infections were found in 153 cases (6.0 %). Trend modelling of the API for complicated malaria for all parasite species showed a non-significant increase throughout the years (APC 14.4 %; 95 % CI -4.3 to 36.6 %). Complicated malaria individuals were mostly males (62.2 %) and young adults (median age of 23 years). Notably, 72.4 % of the patients attended for malaria diagnosis >72 h after symptoms onset and 17 % reported malaria episodes in the last 30 days. All patients received anti-malarial treatment, but only 40 % received the first-line as recommended by the Colombian guidelines. Overall, hepatic and renal complications were the most common severe manifestations (63.6 %). Whereas hepatic and pulmonary complications were more common in P. vivax infections, renal and cerebral complications were significantly more frequent in patients with P. falciparum. In contrast with mono-infected patients, severe anaemia and shock were more frequent in patients with mixed infection.

Conclusion: In contrast with the malaria-decreasing trend over the last years, the complicated malaria trend showed a non-significant annual increase. Therefore, in addition to existing national policies on early diagnosis and prompt anti-malarial treatment, more efforts have to be committed addressing the delayed diagnosis and inadequate treatment found in this study. Improving malaria notification forms, medical assistance skills, and capacity should be prioritized.

Keywords: Colombia; Complicated malaria; Malaria surveillance; Plasmodium falciparum; Plasmodium vivax.

Fig. 1

Malaria cases in Colombia. The number of total malaria cases (a) and complicated malaria cases (b) reported monthly between 2007 and 2013 are shown. Black dashed line (b), corresponds to the number of malaria-related deaths per year. c Percentage of complicated malaria cases over total cases according to the parasite species

Fig. 2

Distribution of complicated malaria cases in Colombia. Percentage ranges of complicated malaria cases between 2007 and 2013 are shown for different regions in Colombia. The five departments reporting the highest number of cases are shown

Fig. 3

Parasite species distribution according to age. Percentage of complicated malaria cases with P. falciparum, P. vivax or mixed infections for 5-year age groups are shown. Black line corresponds to the percentage of total malaria cases (uncomplicated plus complicated) per group

Fig. 4

Trend of the API for complicated malaria. The observed (solid lines) and modelled (dotted lines) annual parasite incidence (API) for 100,000 habitants are shown. APC annual percent change