Diagnosis and therapy for hospitalized imported malaria in adults in Italy

Imported malaria definition and minimum data for surveillance

The mobility of malaria-infected individuals poses challenges to elimination campaigns by way of spreading parasite drug resistance, straining country-to-country collaboration, and making routine data collection difficult, especially in resource-poor settings. Nevertheless, no concerted effort has been made to develop a common framework to define the spatial and temporal components of an imported malaria case and recommend the minimum data needed to identify it. We conducted a scoping review of imported malaria literature from 2010 to 2020 which showed that definitions vary widely, and local capabilities of detecting importation are often restricted in low-income countries. Following this, we propose a common definition for imported malaria and the minimum data required to identify a case, depending on the country's capability of conducting an epidemiological investigation. Lastly, we utilize the proposed definition using data from Brazil to demonstrate both the feasibility and the importance of tracking imported cases. The case of Brazil highlights the capabilities of regular surveillance systems to monitor importation, but also the need to regularly use these data for informing local responses. Supporting countries to use regularly collected data and adopt a common definition is paramount to tackling the importation of malaria cases and achieving elimination goals set forth by the World Health Organization.

The value of lamp to rule out imported malaria diagnosis: a retrospective observational study in Milan, Italy

BACKGROUND

The diagnosis of malaria in returning travellers could be a challenge in non-endemic settings. We aimed to assess the performance of LAMP in comparison with standard conventional diagnostic methods using real-time-polymerase chain reaction (PCR) in case of discordant results.

METHODS

All travellers returning from malaria-endemic areas who presented to our Emergency Department (ED) from January 2017 to December 2020 with signs and symptoms suggestive for malaria were included. Blood microscopy was the reference diagnostic method applied at our laboratory with LAMP implemented as an additional method to aid in malaria diagnosis. PCR was employed only in case of between test's discordant results. Sensitivity and specificity of microscopy compared to LAMP were calculated with the confidence interval of 95%.

RESULTS

Four-hundred and eight patients (55.6% male, median age 42 years) were screened for malaria. The diagnosis was confirmed in 49 cases (12%): 44 cases (90%) caused by Plasmodium falciparum. Peripheral blood smear missed to identify three malaria cases, which tested positive with LAMP and PCR. One case of malaria caused by P. malariae in a naive tourist, one case by P. falciparum in a semi-immune pregnant women and one case by P. falciparum in a previously treated semi-immune patient. All the discordant cases were characterized by a very low parasitaemia. Microscopy when compared to LAMP showed a sensitivity of 93.9% (95% confidence interval (CI) 83.1-98.7%) and a specificity of 100% (95% CI 98.9-100%).

CONCLUSIONS

In our non-endemic setting LAMP was able to identify malaria cases with low-level parasitaemia otherwise missed by blood microscopy.

Severe Plasmodium falciparum malaria in the intensive care unit: A 6-year experience in Milano, Italy

BACKGROUND

Severe imported Plasmodium falciparum malaria is a potentially life-threatening disease with a reported mortality rate of 5-10% when patients are admitted to the Intensive Care Unit.

METHODS

To retrospectively review the clinical aspects, the value of severity predictive scores and the management of patients with severe P. falciparum malaria admitted to an ICU in Milano, Italy between January 2010 and December 2015.

RESULTS

Twelve patients were included: seven were male and five female with a median age of 43 years. All were initially treated with intravenous quinine. Median parasitaemia upon admission was 14,5% (range 1-20%). At the time of ICU admission, 3 patients (25%) had 5 or more World Health Organization criteria for severe malaria while another 6 of them developed one or more of the latter during their stay in ICU. Five required mechanical ventilation because of respiratory failure due to ARDS. Four patients required renal replacement therapy. Three patients underwent blood exchange transfusion. All patients survived.

CONCLUSIONS

Our retrospective evaluation of adults patients admitted to the ICU with severe imported P. falciparum malaria demonstrated a favourable outcome. Severity predictive scores currently in use probably overestimate the risk of malaria mortality in patients treated in health care systems of high income countries.

Malaria and other febrile diseases among travellers: the experience of a reference centre located outside the Brazilian Amazon Region

BACKGROUND

Malaria is endemic in countries located in tropical and sub-tropical regions. The increasing flow of domestic and international travellers has made malaria a relevant health problem even in non-endemic regions. Malaria has been described as the main diagnosis among travellers presenting febrile diseases after returning from tropical countries. In Brazil, malaria transmission occurs mainly in the Amazon region. Outside this area, malaria transmission is of low magnitude.

METHODS

This cross-sectional study aimed to describe the experience in the diagnosis of malaria in a reference centre located outside the Brazilian Amazon Region, emphasizing the differences in clinical and laboratory markers between cases of malaria and those of other febrile diseases (OFD). Medical charts from adult patients (≥18 years) who underwent a thick smear test (TST) for malaria, between January 2001 and December 2014, were retrospectively reviewed.

RESULTS

A total of 458 cases referred to perform the TST were included. Malaria was diagnosed in 193 (42 %) episodes. The remaining 265 episodes (58 %) were grouped as OFD. The majority of malaria episodes were acquired in the Brazilian Amazon Region. The median time between the onset of symptoms and the TST was 7 days. Only 53 (11.5 %) episodes were tested within the first 48 h after symptom onset. Comparing malaria with OFD, jaundice, nausea, vomiting, and reports of fever were more prevalent in the malaria group. Low platelet count and elevated bilirubin levels were also related to the diagnosis of malaria.

CONCLUSIONS

The results indicate that outside the endemic area travellers presenting febrile disease suspected of being malaria underwent diagnostic test after considerable delay. The reporting of fever combined with a recent visit to an endemic area should promptly evoke the hypothesis of malaria. In these cases, specific diagnostic tests for malaria should be a priority. For cases that jump this step, the presence of elevated bilirubin or thrombocytopaenia should also indicate a diagnosis of malaria.

Malaria in a tertiary hospital in Singapore--clinical presentation, treatment and outcome: an eleven year retrospective review

BACKGROUND

Malaria remains a global health threat and poses significant health risks even in non-endemic regions like Singapore.

METHODS

A retrospective analysis of 214 patients with smear-positive malaria treated at Singapore General Hospital (SGH) between year 2000 and 2010.

RESULTS

One hundred and sixty-seven (78%) patients were male; median age was 35 y (range, 25–52 y). Sixty-four (41%) patients had past history of treated malaria. Seven (4.9%) patients did not travel out of Singapore. One hundred and twenty-seven (76.5%) cases of malaria were acquired in Southeast Asia (SEA) and the Indian subcontinent. There were 127 (59.3%) Plasmodium vivax, 83 (38.8%) Plasmodium falciparum, 1 (0.3%) Plasmodium malariae and 3 (1.4%) mixed infections. Fever was the most common symptom and thrombocytopaenia was the most common laboratory finding. There were 43 severe and 171 uncomplicated cases of malaria, including 8 severe P. vivax cases. Those with severe malaria were older, stayed longer in hospital, had a higher percentage parasitaemia and took longer to clear the parasite. The diagnosis of malaria was suspected at the first contact with healthcare provider in 194 (91.9%) cases. Sixty-one (85.9%) patients with P. falciparum infection received combination anti-malarial therapy and 109 (98.2%) of patients with P. vivax received primaquine for hypnozoite clearance in combination with schizontocidal agent. All the patients survived.

CONCLUSION

In this study, P. vivax was the most common cause of malaria. Severe P. vivax was not uncommon. Cryptic transmission of malaria exists, highlighting the importance of continued vigilance, malaria surveillance and vector control. Early recognition of malaria improved the overall outcome.

Imported malaria in Poland 2003 to 2011: implications of different travel patterns

BACKGROUND

The number of imported malaria cases in Poland compared with other European countries remains low. However, in view of the high mortality and the large proportion of severe clinical forms, a better understanding of the problem is required.

METHODS

Data reported to the surveillance system in Poland between 2003 and 2011 were reviewed retrospectively. All cases were laboratory confirmed as outlined by the EU case definition. Statistical analysis was performed using Epi Info 3.5.3 and STATA 10.

RESULTS

A total of 189 confirmed malaria cases, including 5 that were fatal, were reported in Poland during the study period. All cases were imported: 72% came from Africa. Among cases with a species-specific diagnosis, 118 (73%) were caused by Plasmodium falciparum. The median age of individuals afflicted was 36 years and 74% were males. Most cases occurred among work-related travelers (40%) or tourists (38%). Individuals born in malaria-endemic countries constituted 12% of all cases. The severe malaria form was identified in 23% of all cases and was more frequent among cases caused by P. falciparum (32%), in people older than 50 years (39%), and in cases when diagnosis was delayed (36%). The severe form occurred only in 9% of cases originating from malaria-endemic countries and there were no fatalities in this group. Fatal outcomes were associated with a delay in diagnosis (fatality = 10.5%) and falciparum malaria (fatality = 4%). Most of the delays resulted from a delay in seeking medical care, and less frequently due to misdiagnosis.

CONCLUSIONS

Tourists and work-related travelers make up most of the malaria patients in Poland and they are at a greater risk of the severe form of malaria and consequently death, possibly due to the lack of immunity. Delayed diagnosis is associated with mortality, implying low awareness of the threat that malaria poses, both among patients and doctors.

Sensitivity of parasitological tests in imported Plasmodium vivax malaria in adults and impact of chemoprophylaxis and attack type

BACKGROUND

Plasmodium vivax is the second most common species among cases of imported malaria diagnosed in Europe. The objective of this study is to describe the sensitivity of the parasitological tests in imported P. vivax malaria, and the impact of chemoprophylaxis and attack type (primary infection or relapse).

METHODS

A retrospective study included the imported vivax malaria cases admitted in a French military hospital between 2001 and 2013. The reference diagnosis method was microscopy corrected by polymerase chain reaction (PCR). Thin and thick blood films examination, quantitative buffy coat (QBC) test, and a rapid diagnostic test (RDT) had been systematically performed. PCR had been carried out for ambiguous profiles.

RESULTS

Eighty-nine cases recorded from 78 patients were included, 65 of them having recently traveled to French Guyana. Forty-two patients had properly followed chemoprophylaxis. Forty-six cases were primary infections while 43 were relapses. The sensitivity was 91% for the thin blood smear, 96% for the concentration techniques (Giemsa thick blood smear and QBC test), and 76% for the RDT. The combination of the three conventional tools has an imperfect sensitivity, both for the positive diagnosis of malaria (96%) and for the diagnosis of vivax species (80%). In 4% of the cases, the positive diagnosis was established only by the PCR. The species identification was established in 20% by the PCR. The sensibility of thin blood smear and of RDT decreased significantly with full compliance of chemoprophylaxis or primary infection, whereas the decrease of sensibility of concentration techniques was not significant.

CONCLUSIONS

This study illustrates the difficulties encountered in vivax malaria diagnosis, especially in patients who properly followed chemoprophylaxis or with primary infection due to a lower parasitemia. It underlines the lack of sensitivity of RDT for P. vivax and emphasizes the need for systematically combining various diagnosis methods.

Elimination therapy for the endemic malarias

Most malaria diagnosed outside endemic zones occurs in patients experiencing the consequences of what was likely a single infectious bite by an anopheline mosquito. A single species of parasite is nearly always involved and expert opinion on malaria chemotherapy uniformly prescribes species- and stage-specific treatments. However the vast majority of people experiencing malaria, those resident in endemic zones, do so repeatedly and very often with the involvement of two or more species and stages of parasite. Silent forms of these infections-asymptomatic and beyond the reach of diagnostics-may accumulate to form substantial and unchallenged reservoirs of infection. In such settings treating only the species and stage of malaria revealed by diagnosis and not others may not be sensible or appropriate. Developing therapeutic strategies that address all species and stages independently of diagnostic evidence may substantially improve the effectiveness of the control and elimination of endemic malaria.

Migration and malaria in europe

The proportion of imported malaria cases due to immigrants in Europe has increased during the lasts decades, with higher rates associated with settled immigrants who travel to visit friends and relatives (VFRs) in their country of origin. Cases are mainly due to P. falciparum and Sub-Saharan Africa is the most common origin. Clinically, malaria in immigrants is characterised by a mild clinical presentation including asymptomatic or delayed malaria cases and low parasitic levels. These characteristics may be explained by a semi-immunity acquired after long periods of time exposed to stable malaria transmission. Malaria cases among immigrants, even asymptomatic patients with sub-microscopic parasitemia, could increase the risk of transmission and cause the reintroduction of malaria in certain areas that have adequate vectors and climate conditions. Moreover, imported malaria cases in immigrants can also play an important role in the non-vector transmission out of endemic areas, through blood transfusions, organ transplantation or congenital transmission or occupational exposures. Consequently, outside of endemic areas, malaria screening should be carried out among recently arrived immigrants coming from malaria endemic countries. The aim of screening is to reduce the risk of clinical malaria in the individual as well as to prevent autochthonous transmission of malaria in areas where it has been eradicated.