Status of imported malaria on Réunion Island in 2016

Prevention of re-establishment of malaria

The current consensus on prevention of re-establishment of malaria is based on the following principles: (1) Fundamental role of general health services; (2) Surveillance; (3) Vector control; (4) Border actions; (5) Intersectoral collaboration. These principles are critically reviewed, and it is pointed out that alertness of the general health services to suspected malaria (vigilance) needs to be maintained everywhere, while health education is rational only if targeting high-risk sub-populations. It is argued that prevention of re-establishment of malaria transmission should be integrated with prevention of malaria mortality in cases of imported malaria, and that this requires collaboration with entities dealing with travellers’ health and the availability of chemoprophylaxis and other measures for travellers to malaria endemic countries.

Prevention of re-establishment of malaria: historical perspective and future prospects

Prevention of re-establishment (POR) refers to the prevention of malaria outbreak/epidemic occurrence or preventing re-establishment of indigenous malaria in a malaria-free country. Understanding the effectiveness of the various strategies used for POR is, therefore, of vital importance to countries certified as "malaria-free" or to the countries to be thus certified in the near future. This review is based on extensive review of literature on both the POR strategies and elimination schemes of countries, (i) that have reached malaria-free status (e.g. Armenia, Mauritius, Sri Lanka), (ii) those that are reaching pre-elimination stage (e.g. South Korea), and (iii) countries at the control phase (e.g. India). History has clearly shown that poorly implemented POR programmes can result in deadly consequences (e.g. Sri Lanka); conversely, there are examples of robust POR programmes that have sustained malaria free status that can serve as examples to countries working toward elimination. Countries awaiting malaria elimination status should pre-plan their POR strategies. Malaria-free countries face the risk of resurgence mostly due to imported malaria cases; thus, a robust passenger screening programme and cross border collaborations are crucial in a POR setting. In addition, sustained vigilance, and continued funding for the national anti-malarial campaign programme and for related research is of vital importance for POR. With distinct intrinsic potential for malaria in each country, tailor-made POR programmes are built through continuous and robust epidemiological and entomological surveillance, particularly in countries such as Sri Lanka with increased receptivity and vulnerability for malaria transmission. In summary, across all five countries under scrutiny, common strengths of the POR programmes are (i) a multipronged approach, (ii) strong passive, active, and activated passive case detection, (iii) Indoor residual spraying (IRS), and (iv) health education/awareness programmes.

A systematic review of factors affecting adherence to malaria chemoprophylaxis amongst travellers from non-endemic countries

Background

The aim of this systematic review was to identify predictors of actual or intended adherence with malaria chemoprophylaxis amongst travellers from non-endemic countries visiting endemic countries.

Methods

A systematic review of the literature was conducted using MEDLINE, Embase, PsycINFO and Global Health databases for studies published up to April 2019. Studies were included if they assessed reasons for adherence among people travelling from a country where malaria was not endemic to a country where it was.

Results

Thirty-two studies were included. Predictors of adherence were categorized as relating to either the nature of the travel or the traveller themselves. The three main predictors associated with nature of travel included: destination (e.g. country visited, urban vs rural areas), length of travel and type of travel (e.g. package vs backpacking holiday). The four main traveller-associated predictors were: age, reason for travel (e.g. business, leisure or visiting friends and relatives), perceived risk of catching malaria and experienced or expected medication effects.

Conclusions

In order to improve adherence, clinicians should focus on travellers who are least likely to exhibit adherent behaviour. This includes travellers visiting destinations known to have lower adherence figures (such as rural areas), backpackers, business travellers, younger travellers and those travelling for longer periods of time. They should also check to ensure travellers’ perceptions of the risks of malaria are realistic. Where appropriate, misperceptions (such as believing that curing malaria is easier than taking prophylaxis or that travellers visiting relatives have some level of innate immunity) should be corrected. All travellers should be informed of the potential side-effects of medication and given guidance on why it is nonetheless beneficial to continue to take prophylaxis. Further research is required to test interventions to improve adherence.

Imported malaria cases: the connection with the European ex-colonies

Background

Imported malaria is increasing in non-endemic areas due to the increment of international travels, migration and, probably, other unknown factors. The objective of this study was to describe the epidemiological and clinical characteristics of malaria cases in a region of Spain; analyse the possible association between the variables of interest; compare this series with others; and evaluate the characteristics of imported malaria cases according to the country of origin, particularly cases from Equatorial Guinea (Spanish ex-colony) and from the rest of sub-Saharan Africa.

Methods

A descriptive observational study was carried out with a retrospective data collection of cases of malaria reported in Aragon from 1996 to 2017. Univariate and bivariate analysis of clinical–epidemiological variables was performed. In addition, an analysis of cases from sub-Saharan Africa was carried out using logistic regression, calculating odds ratio with its 95% confidence interval.

Results

609 cases of malaria were recorded in Aragon from 1996 to 2017. An autochthonous case in 2010. 50.33% were between 15 and 39 years old. 45.65% of the cases were notified of the 4-weeks 9 to 12. 82.6% reside in the main province, urban area, of which 65.4% were VFR (Visiting Friends and Relatives), 23.8% new immigrants and 10.9% travellers. The infectious Plasmodium species par excellence was Plasmodium falciparum (88%). Analysing the cases from sub-Saharan Africa (95.2% of the total), 48.1% were from Equatorial Guinea. Comparing these with the cases from the rest of sub-Saharan Africa, it was observed that the cases from the Spanish ex-colony have association with the female gender, being under 5 years old, residing in the main province (urban area) and being a new immigrant.

Conclusions

The epidemiological profile of imported malaria cases can be defined as VFR between 15 and 39 years old, coming from sub-Saharan Africa, particularly from Equatorial Guinea. Immigrants education about the importance of chemoprophylaxis when travelling to visit friends and relatives, emphasizing on those who are originally from the ex-colonies of destination country, is necessary; as well as to raise awareness among health professionals to make advice in consultations, specially before summer vacations.

Spatiotemporal characterisation and risk factor analysis of malaria outbreak in Cabo Verde in 2017

Background

Cabo Verde is a country that has been in the pre-elimination stage of malaria since the year 2000. The country is still reporting cases, particularly in the capital of Praia, where more than 50% of the national population live. This study aims to examine the spatial and temporal epidemiological profile of malaria across the country during the 2017 outbreak and to analyse the risk factors, which may have influenced the trend in malaria cases.

Methods

Longitudinal data collected from all malaria cases in Cabo Verde for the year 2017 were used in this study. The epidemiological characteristics of the cases were analysed. Local and spatial clusters of malaria from Praia were detected by applying the Cluster and Outlier Analysis (Anselin Local Moran's I) to determine the spatial clustering pattern. We then used the Pearson correlation coefficient to analyse the relationship between malaria cases and meteorological variables to identify underlying drivers.

Results

In 2017, 446 cases of malaria were reported in Cabo Verde with the peak of cases in October. These cases were primarily Plasmodium falciparum infections. Of these cases, 423 were indigenous infections recorded in Praia, while 23 were imported malaria cases from different African countries. One case of P. vivax infection was imported from Brazil. Spatial autocorrelation analysis revealed a cluster of high-high malaria cases in the centre of the city. Malaria case occurrence has a very weak correlation (r = 0.16) with breeding site location. Most of the cases (69.9%, R ² = 0.699) were explained by the local environmental condition, with temperature being the primary risk factor followed by relative humidity. A moderately positive relationship was noted with the total pluviometry, while wind speed had a strong negative influence on malaria infections.

Conclusions

In Cabo Verde, malaria remains a serious public health issue, especially in Praia. The high number of cases recorded in 2017 demonstrates the fragility of the situation and the challenges to eliminating indigenous malaria cases and preventing imported cases. Mosquito breeding sites have been the main risk factor, while temperature and precipitation were positively associated with malaria infection. In light of this study, there is an urgent need to reinforce control strategies to achieve the elimination goal in the country.