Success of malaria chemoprophylaxis for outbound civil and military travellers in prevention of reintroduction of malaria in Sri Lanka

Preventing the re-establishment of malaria during the COVID-19 pandemic in Sri Lanka: implications for health security

BACKGROUND

The COVID-19 pandemic-with its first reported case in Sri Lanka in March 2020-had the potential to impact the risk of re-establishing malaria, a disease which was eliminated from Sri Lanka in 2012. Post-elimination, the country remains highly vulnerable to a return of malaria on account of high vector mosquito densities and the inflow of imported malaria cases.

METHODS

Parallels between COVID-19 and malaria after its elimination as health security threats were drawn, and the many ways in which the COVID-19 pandemic impacted the prevention of re-establishment of malaria programmes in the country in 2020 were examined. The implications of this experience for global health security are analysed.

RESULTS

In 2020, imported malaria cases were fewer than in the previous 3 years, due to restrictions on international travel. Yet, a high level of malaria case and entomological surveillance was sustained through surveillance strategies modified to focus on quarantine centers, in response to the pandemic. As a result, more imported malaria cases were detected by active case detection than by passive surveillance. Some of the operational shifts adopted by the Anti Malaria Campaign were moving rapidly into functioning as an intersectoral player by reinforcing its collaborations with the Ministries of Aviation and Defense, switching to the use of online communication systems, and integrating and synergizing its field activities with the COVID-19 control programme.

CONCLUSIONS

The experience highlights the need for disease control programmes to be agile, flexible and responsive, and underscores the importance of maintaining even a lean focal programme for diseases such as malaria after they have been eliminated. Sustaining public health leadership and robust technological capacities in communication and data management were paramount in preventing the disruption of the malaria prevention programme during the pandemic and sustaining the malaria-free status of the country.

An epidemiological analysis of severe imported malaria infections in Sri Lanka, after malaria elimination

BACKGROUND

Imported malaria continues to be reported in Sri Lanka after it was eliminated in 2012, and a few progress to life-threatening severe malaria.

METHODS

Data on imported malaria cases reported in Sri Lanka from 2013 to 2023 were extracted from the national malaria database maintained by the Anti Malaria Campaign (AMC) of Sri Lanka. Case data of severe malaria as defined by the World Health Organization were analysed with regard to patients' general characteristics and their health-seeking behaviour, and the latter compared with that of uncomplicated malaria patients. Details of the last three cases of severe malaria in 2023 are presented.

RESULTS

532 imported malaria cases were diagnosed over 11 years (2013-2023); 46 (8.6%) were severe malaria, of which 45 were Plasmodium falciparum and one Plasmodium vivax. Most severe malaria infections were acquired in Africa. All but one were males, and a majority (87%) were 26-60 years of age. They were mainly Sri Lankan nationals (82.6%). Just over half (56.5%) were treated at government hospitals. The average time between arrival of the person in Sri Lanka and onset of illness was 4 days. 29 cases of severe malaria were compared with 165 uncomplicated malaria cases reported from 2015 to 2023. On average both severe and uncomplicated malaria patients consulted a physician equally early (mean = 1 day) with 93.3% of severe malaria doing so within 3 days. However, the time from the point of consulting a physician to diagnosis of malaria was significantly longer (median 4 days) in severe malaria patients compared to uncomplicated patients (median 1 day) (p = 0.012) as was the time from onset of illness to diagnosis (p = 0.042). All severe patients recovered without sequelae except for one who died.

CONCLUSIONS

The risk of severe malaria among imported cases increases significantly beyond 5 days from the onset of symptoms. Although patients consult a physician early, malaria diagnosis tends to be delayed by physicians because it is now a rare disease. Good access to expert clinical care has maintained case fatality rates of severe malaria at par with those reported elsewhere.

Questionnaire-Based Analysis of Adverse Events and Compliance with Malaria Chemoprophylaxis in Taiwan

Malaria was eradicated in Taiwan in 1952; however, imported malaria cases are reported every year. The subtropical climate in Taiwan permits mosquito propagation and possible outbreaks of mosquito-borne diseases. The aim of this study was to investigate travelers' compliance and side effects of malaria prophylaxis to prevent a malaria outbreak in Taiwan. In this prospective study, we enrolled travelers who visited our travel clinic before going to malarious areas. A total of 161 questionnaires were collected and analyzed. Associations between the occurrence of side effects and compliance with antimalarial drugs were analyzed. Adjusted odds ratios were calculated after adjusting for potential risk factors in multiple logistic regression analysis. Of the 161 enrolled travelers, 58 (36.0%) reported side effects. Insomnia, somnolence, irritability, nausea, and anorexia were associated with poor compliance. Mefloquine was not associated with more neuropsychological side effects than doxycycline. Multiple logistic regression analysis showed that chemoprophylaxis compliance was affected by a younger age, visiting friends and relatives, visiting the travel clinic more than 1 week before the trip, and preferring to use the same antimalarial regimen on the next trip. Our findings could provide information to travelers besides labeled side effects to improve compliance with malaria prophylaxis and consequently help to prevent malaria outbreaks in Taiwan.

Compliance with Primary Malaria Chemoprophylaxis: Is Weekly Prophylaxis Better Than Daily Prophylaxis?

BACKGROUND

Chemoprophylaxis is an effective tool for individuals to minimize their risk of contracting malaria and serves an important public health role in preventing imported malaria. Yet, it is only effective if the traveller is fully compliant with the prescribed regimen. For many destinations, a choice of prophylactic agents is available, so historical compliance data can be helpful for both physicians and travellers to make an informed decision.

METHODS

We analyzed the historical self-reported compliance data for six chemoprophylactic agents currently recommended by CDC for primary malaria chemoprophylaxis by searching PubMed, Embase, CINAHL, Web of Science, and Scopus for observational studies reporting on travelers within the last 25 years. The quality of data was graded as "good" or "poor" using the NIH quality assessment tool for cohort and cross-sectional studies. Cumulative compliance data were compiled for all studies (gross compliance) and the subgroup of studies with "good" quality evidence (refined compliance). Subgroup analyses were performed for weekly vs daily administered regimens, between military and civilian travelers, and across each prophylactic agent.

RESULTS

Twenty-four eligible studies assessed compliance for mefloquine (n=20), atovaquone-proguanil (n=11), doxycycline (n=13), and chloroquine (n=3). No studies were found for primaquine or tafenoquine. Both gross and refined compliance were significantly better for weekly regimens than daily regimens (P<0.0001). Stopping chemoprophylaxis due to adverse events was significantly more for doxycycline (P<0.0001) compared to other drugs. Compliance was significantly worse in military travelers, but they were also more likely to be prescribed doxycycline.

CONCLUSION

Malaria chemoprophylaxis for a traveler should depend on prevailing resistance patterns at destination, current national guidelines, and patient preferences. However, when there is a choice, historical compliance data are useful to select a regimen that the traveler is more likely to comply with.