Chronic malaria and hyper-reactive malarial splenomegaly: a retrospective study on the largest series observed in a non-endemic country

Abstract

BackgroundChronic malaria is usually defined as a long-term malarial infection in semi-immune subjects, usually without fever or other acute symptoms. The untreated infection may evolve to hyper-reactive malarial splenomegaly (HMS), a life-threatening complication. This paper describes the largest series of HMS ever observed outside endemic countries, and the clinical outcome after a single anti-malarial treatment. Contrarily to most authors, still reporting the traditional, long-term treatment, regardless possible further exposure, the patients in this series did not receive any further prophylaxis if they were not re-exposed to malaria infection.MethodsA retrospective, longitudinal study, describing all patients with HMS diagnosed at the Centre for Tropical Diseases of Negrar, Verona, took place over a 25-year period. HMS was defined by a longitudinal spleen diameter ≥16 cm, IgM ≥ 2.5 g/L, anti-malarial antibody titre ≥160, exclusion of other causes of splenomegaly. The short-term (≤6 months) clinical outcome after a single anti-malarial treatment was analysed and so was the long-term outcome of subjects re-exposed to malaria and submitted or not to anti-malarial prophylaxis or intermittent treatment. The association of the outcome with the main independent variables was first assessed with univariate analysis. Logistic regression was also performed.ResultsForty-four subjects with HMS were retrieved. Of those with a short-term follow-up visit (<6 months, median 43 days) available before returning to endemic areas, 20/22 resulted improved/cured, two were unchanged. Of 22 expatriates seen at long-term follow-up after re-exposure, 18 were improved/cured, including eight out of nine who had followed an anti-malarial prophylaxis and 10/13 who had opted for the alternative of an intermittent treatment.ConclusionHMS is the most severe form of chronic malaria. A single anti-malarial treatment is probably adequate to treat HMS in the absence of re-exposure, while an adequate prophylaxis is necessary for patients exposed again to malaria transmission. Intermittent treatment would probably be the only viable approach in endemic countries.

Dynamics of antimalarial antibodies in non-immune patients during and after a first and unique P. falciparum malaria episode.

“…This is typically observed in chronic malaria infection [13]. Subjects with a persistently high antibody titre would be automatically excluded from blood donation, moreover they might benefit from an effective antimalarial treatment, even in case of failure to detect circulating plasmodia, antigen or DNA [13]. Of course, a change of the current policy would need more evidence to be suggested, but a periodical serologic testing might be suggested especially for donors with particularly requested blood groups, also considering that serologic tests are available at a reasonable cost.…”

“…It is reasonable to assume that chronic carriers of a very low or undetectable parasitemia (who might represent a theoretical risk of transmission through blood donation) would maintain a high antibody titre. This is typically observed in chronic malaria infection [13]. Subjects with a persistently high antibody titre would be automatically excluded from blood donation, moreover they might benefit from an effective antimalarial treatment, even in case of failure to detect circulating plasmodia, antigen or DNA [13].…”

Dynamics of antimalarial antibodies in non-immune patients during and after a first and unique P. falciparum malaria episode

“…It is reasonable to assume that chronic carriers of a very low or undetectable parasitemia (who might represent a theoretical risk of transmission through blood donation) would maintain a high antibody titre. This is typically observed in chronic malaria infection [11]. Subjects with a persistently high antibody titre would be automatically excluded from blood donation, moreover they might benefit from an effective antimalarial treatment, even in case of failure to detect circulating plasmodia, antigen or DNA [11].…”

“…This is typically observed in chronic malaria infection [11]. Subjects with a persistently high antibody titre would be automatically excluded from blood donation, moreover they might benefit from an effective antimalarial treatment, even in case of failure to detect circulating plasmodia, antigen or DNA [11].…”

A 48 year old male with jaundice and exertional chest pain

“…2, 3 Chronic presence of malarial parasites is the cause of mild hemolysis leading to asymptomatic anemia and inclines the affected individuals to other infections. 4 Patient with malaria may present with mild jaundice which is frequently missed clinically. Such jaundice is quite common and may be detected in 20-40% of the cases.…”