Transfusion-induced Plasmodium falciparum malaria in a beta thalassaemia patient during the prevention of re-establishment phase in Sri Lanka

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.

Factors impacting sustained coverage in the context of donor transitions: experience from Sri Lanka

Although not reliant on donor funding for health, the external assistance that Sri Lanka receives contributes to the improvement of the health system and health outcomes. In this study, we evaluated transition experiences of the expanded programme on immunization (EPI) that received Gavi funding to expand the vaccine portfolio and the Anti-Malaria Campaign (AMC) that received funding from the Global Fund for AIDS, Tuberculosis and Malaria to scale-up interventions to target and achieve malaria elimination. We assessed if EPI and AMC programmes were able to sustain coverage of previously donor-funded interventions post-transition and explain the facilitators and barriers that contribute to this. We used a mixed methods approach using quantitative data to assess coverage indicators and the financing mix of the health programmes and qualitative analysis guided by a framework informed by the Walt and Gilson policy triangle that brought together document review and in-depth interviews to identify facilitators and barriers to transition success. The EPI programme showed sustained coverage of Gavi-funded vaccines post-transition and the funding gap was bridged by mobilizing domestic financing facilitated by the Gavi co-financing mechanism, full integration within existing service delivery structures, well-established and favourable pharmaceutical procurement processes for the public sector and stewardship and financial advocacy by technically competent managers. Although the absence of indigenous cases of malaria since 2012 suggests overall programme success, the AMC showed mixed transition success in relation to its different programme components. Donor-supported programme components requiring mobilization of operational expenses, facilitated by early financial planning, were successfully transitioned (e.g. entomological and parasitological surveillance) given COVID-19-related constraints. Other key programme components, such as research, training, education and awareness that are dependent on non-operational expenses are lagging behind. Additionally, concerns of AMC's future financial sustainability within the current structure remain in the context of low malaria burden.

A malaria death due to an imported Plasmodium falciparum infection in Sri Lanka during the prevention of re-establishment phase of malaria

BACKGROUND

Sri Lanka has maintained a rigorous programme to prevent the re-establishment of malaria ever since the disease was eliminated in October 2012. It includes efforts to sustain case surveillance to ensure early diagnosis and management of malaria. Yet, in April of 2023 the death occurred of an individual with imported malaria.

CASE PRESENTATION

The deceased was a 37-year-old Sri Lankan male who returned to Sri Lanka on the 10th of April after a business trip to several countries including Tanzania. He was febrile on arrival and consulted three Allopathic Medical Practitioners in succession in his home town in the Western Province of Sri Lanka, over a period of 5 days starting from the very day that he arrived in the country. Malaria was not tested for at any of these consultations and his clinical condition deteriorated. On the evening of 14th of April he was admitted to the medical intensive care unit of a major private hospital in the capital city of Colombo with multiple organ failure. There, on a request by the treating physician blood was tested for malaria and reported early the next morning as Plasmodium falciparum malaria with a high parasitaemia (> 10%). The patient died shortly after on the 15th of April before any anti-malarial medication was administered. The deceased had been a frequent business traveller to Africa, but with no past history of malaria. He had not taken chemoprophylaxis for malaria on this or previous travels to Africa.

DISCUSSION

The patient's P. falciparum infection progressed rapidly over 5 days of arriving in Sri Lanka leading to severe malaria without being diagnosed, despite him seeking healthcare from three different Medical Practitioners. Finally, a diagnosis of malaria was made on admission to an intensive care unit; the patient died before anti-malarial medicines were administered.

CONCLUSIONS

This first death due to severe P. falciparum malaria reported in Sri Lanka after elimination of the disease was due to the delay in diagnosing malaria.

Biology, bionomics and life-table studies of Anopheles stephensi (Diptera: Culicidae) in Sri Lanka and estimating the vectorial potential using mathematical approximations

BACKGROUND

Anopheles stephensi is an invasive mosquito in Sri Lanka that can potentially transmit malaria. The transmission intensity is linked with biology, bionomic and behavioral aspects of a vector that are associated with the Vectorial Capacity (VC). However, the influence of larval conditions eventually affects the vectorial potential of An. stephensi are not well understood.

METHODS

A colony of An. stephensi was established at the Regional Centre of the Open University of Sri Lanka, Jaffna District. The colony was maintained under confined conditions according to standard protocols. Biotypes of An. stephensi were characterized by referring to the number of egg ridges. Information on (a) biological aspects of eggs (duration for egg hatching, egg development and hatchability), (b) larval development time, larval survivorship pupation success, resting depth of larvae), (c) pupae (adult emergence rate, average time for adult emergence) and (d) adults (biting frequency, mating success gonotrophic cycle, fecundity, duration for egg-laying, percentage of sexes, adult survival/longevity) were evaluated under life-table analysis. Further, selected morphometric characters of each life cycle stage were recorded from the eggs (length and breadth), larvae (head length, width of head, length of thorax, width of thorax, length of abdomen, width of abdomen, and the total length of larvae), pupae (cephalothoracic length and width) and adults (length & width of wing, thorax and abdomen). The VC was calculated using a mathematical-based approach. Descriptive statistics, General Linear Model (GLM) and independent-sample t-test were used for the statistical analysis.

RESULTS

All three biotypes were identified based on egg morphology. Mysorensis biotype (47%; n = 470) was predominant followed by type (38.1%; n = 381) and intermediate (14.9%; n = 149). The mean egg length (F_(2,997) = 3.56; P = 0.029) and breadth (F_(2,997) = 4.57; P = 0.011) denoted significant differences among the three biotypes. The mating success of females observed was 80.7 ± 4.45%. The mean hatching period was 1.9 ± 0.03 days, with a hatching rate of 86.2 ± 0.77%. Overall, 8.0 ± 0.14 days were required for larval development and 30.3 ± 0.14 h were spent in the pupal stage. The pupation success was 94.5 ± 0.37%, and the majority were males (53.1 ± 0.73%). The mean fecundity was 106.5 ± 6.38 eggs and a gonotrophic cycle of 3.4 ± 0.06 days. The female survival rate was 43.2 ± 2.4%, with a mean biting frequency of 66.6 ± 3.5%. The average VC of adult An. stephensi was estimated to be 18.7.

CONCLUSIONS

The type biotype, which is an effective vector in the Indian subcontinent is present in Sri Lanka. According to the mathematical approximation, An. stephensi found locally has a vectorial capacity of over 18. Therefore, this study warrants the health authorities and vector control programmes to continue the entomological surveys, monitoring of vector densities and implementing appropriate vector control interventions based on biology and bionomic information of vectors.

W. Gunasekera KT, Ranaweera P. Evaluation of a haemozoin-based rapid diagnostic test for diagnosis of imported malaria during the phase of prevention of reestablishment in Sri Lanka

Background

Sri Lanka, an island nation, has eliminated endemic malaria transmission. Maintaining elimination in the continued presence of vectors requires vigilance in screening people travelling from high malaria-risk areas and a rapid response with focal screening for infections identified in the community. Such screening requires accurate and very rapid assays that enable an immediate response. Both microscopy and rapid diagnostic tests (RDTs) have limitations including sensitivity and speed in screening large numbers, while polymerase chain reaction (PCR) is practical only as laboratory confirmation. This study assessed the utility of ‘Gazelle’, a novel rapid malaria assay based on magneto-optical detection of haemozoin, a by-product of malaria parasite metabolism.

Methods

Between October 2020 and March 2021, two groups of individuals were screened for malaria by four methods, namely, microscopy, Rapid Diagnostic Test (RDT), Gazelle and PCR. Passive case detection was carried out for confirmation of diagnosis amongst individuals suspected of having malaria. Individuals at high-risk of acquiring malaria, namely persons returning from malaria endemic countries, were screened by active case detection.

Results

Of the 440 individuals screened for malaria, nine malaria positives were diagnosed by PCR, microscopy and the HRP2 band of RDT, which included five Plasmodium falciparum infections, two Plasmodium ovale, and one each of Plasmodium vivax and Plasmodium malariae. Gazelle correctly detected the P. vivax, P. ovale and P. malariae infections within the 2 min test time, but did not detect two P. falciparum infections giving a sensitivity of 77.8%. Specificity was 100%.

Discussion

The Gazelle, a portable bench top device proved useful to screen a large number of blood samples for non-falciparum parasites within 5 minutes of sample input. Species differentiation, and improvement in P. falciparum detection, will be important to broaden utility.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-022-04283-7.