Biology of Human Malaria Plasmodia Including Plasmodium Knowlesi

Malaria is a vector-borne infection caused by unicellular parasite of the genus Plasmodium. Plasmodia are obligate intracellular parasites that are able to infect and replicate within the erythrocytes after a clinically silent replication phase in the liver. Four species (P.falciparum, P.malariae, P.ovale and P.vivax) are traditionally recognized as responsible of natural infection in human beings but the recent upsurge of P.knowlesi malaria in South-East Asia has led clinicians to consider it as the fifth human malaria parasite. Recent studies in wild-living apes in Africa have revealed that P.falciparum, the most deadly form of human malaria, is not only human-host restricted as previously believed and its phylogenetic lineage is much more complex with new species identified in gorilla, bonobo and chimpanzee. Although less impressive, new data on biology of P.malariae, P.ovale and P.vivax are also emerging and will be briefly discussed in this review

Report of 4 Cases and Review of the Literature

We reviewed the clinical, microbiologic, and outcome characteristics of 72 patients with human immunodeficiency virus (HIV)-associated histoplasmosis (4 newly described) reported in Europe over 20 years (1984-2004). Seven cases (9.7%) were acquired in Europe (autochthonous), whereas the majority involved a history of travel or arrival from endemic areas. The diagnosis of progressive disseminated histoplasmosis (PDH) was made during life in 63 patients (87.5%) and was the acquired immunodeficiency syndrome (AIDS)-presenting illness in 44 (61.1%). Disease was widespread in 66 patients (91.7%) and localized in 6 (8.3%), with the skin being the most frequent site of localized infection. Overall skin involvement was reported in 47.2% of the patients regardless of whether histoplasmosis was acquired in Africa or South America. Reticulonodular or diffuse interstial infiltrates occurred in 52.8%. The diagnosis was made during life by histopathology plus culture in 44 patients (69.8%), histopathology alone in 18 (28.5%), and culture alone in 1 (1.5%). During the induction phase amphotericin B and itraconazole (74.6%) were the single most frequently used drugs. Both drugs were also used either in combination (10.2%) or in sequential therapy (11.8%). Cumulative mortality rate during the induction phase of treatment was 15.2%. Overall, 37 patients died (57.8%); death occurred early in the course in 18 (28.1%). Seven of 40 patients (17.5%) who responded to therapy subsequently relapsed. Autopsy data in 13 patients confirmed the widespread disseminated nature of histoplasmosis (85%) among AIDS patients with a median of 4.5 organs involved. The results of the present report highlight the need to consider the diagnosis of PDH among patients with AIDS in Europe presenting with a febrile illness who have traveled to or who originated from an endemic area

Trends in the Postmortem Diagnosis of Opportunistic Invasive Fungal Infections in Patients With AIDS

Abstract We retrospectively evaluated autopsy-proven invasive fungal infections (IFIs) in patients with AIDS who died between 1984 and 2002. IFIs were identified in 297 (18.2%) of 1,630 autopsies. Their prevalence significantly decreased over time (from 25.0% in 1984–1988 to 15% in 1998–2002; P = .004), mainly owing to a significant decrease in pneumocystosis (P = .017) and cryptococcosis (P = .003), whereas the prevalence of aspergillosis and histoplasmosis remained relatively stable and of candidiasis and zygomycosis tended to increase in the last years (P = .028 and P = .042, respectively). IFIs were suspected or confirmed during life in only 46.8% of the cases; this proportion did not vary significantly over time (P = .320). The infections contributed to the deaths of 103 patients (34.7%), and their global impact on mortality was 6.3%. Of fatal cases, 38 (36.9%) were characterized by missed antemortem diagnoses, 17 (45%) of which met Goldman criteria for class I errors. The epidemiology of IFIs in patients with AIDS is evolving and not completely mirrored by clinical diagnoses or current diagnostic methods. Our results confirm the valuable role of autopsy data, even with highly effective therapies and advanced technologies

Polymerase chain reaction in the diagnosis and prognosis of Mediterranean visceral leishmaniasis in immunocompetent children

OBJECTIVE: To assess the usefulness of a polymerase chain reaction (PCR) assay amplifying the small subunit rRNA coding region of Leishmania species performed on peripheral blood (PB) and bone marrow (BM) aspirates for the diagnosis and follow-up of visceral leishmaniasis (VL) in children living in the Mediterranean basin. DESIGN: A prospective study was conducted on children consecutively hospitalized over a 1-year period at our Infectious Diseases Department in Sicily (Italy) presenting with fever, hepatosplenomegaly, and/or pancytopenia and a positive Leishmania serology (> or =1:40). RESULTS: Among the 14 patients hospitalized with signs and symptoms suggestive of the disease and a positive serology, we identified 10 cases of Mediterranean VL. PCR performed on PB and BM aspirates was positive in all cases and concordant with microscopy and/or culture performed on BM. Leishmania DNA was cleared from PB a median of 6 days after the start of treatment; during follow-up (median: 9 months; range: 6-12 months) 1 child relapsed. In this case, BM PCR remained positive with rapid reappearance of a positive signal also in PB. CONCLUSIONS: PB PCR allows a rapid and noninvasive parasitologic diagnosis of Mediterranean VL among immunocompetent children and is at least as sensitive as a diagnosis made on the basis of BM aspirates. The lack of disappearance from BM and the reappearance of positive PCR on PB is predictive of clinical relapse. Qualitative and semiquantitative PCR may be the standard method for monitoring response to therapy in immunocompetent childre

Imported Loa Loa Filariasis: Three Cases and a Review of Cases Reported in Non-Endemic Countries in the Past 25 Years

Summary Objectives The aim of this study was to highlight the increasing chance of Western physicians encountering patients (both immigrants and expatriates/travelers) seeking help for loiasis. Methods We describe three cases of imported loiasis observed at two hospitals in Italy and France, and present a review of all previously published cases in the medical literature in the last 25 years (1986–2011). The search was performed using PubMed and Scopus databases using the terms " Loa loa " AND "loiasis". Results We reviewed 101 cases of imported loiasis of which 61 (60.4%) were reported from Europe and 31 (30.7%) from the USA. Seventy-five percent of infestations were acquired in three countries: Cameroon, Nigeria, and Gabon. Overall, peripheral blood microfilariae were detected in 61.4% of patients, eosinophilia in 82.1%, eye worm migration in 53.5%, and Calabar swellings in 41.6%. However, Calabar swellings and eosinophilia were more common among expatriates/travelers, whereas African immigrants were more likely to have microfilaremia. Eye worm migration was observed in a similar proportion in the two groups. Only 35 patients (including the three described here) underwent clinical follow-up for a median period of 10.5 months (range 1–84 months); clinical relapse occurred in three of these patients and persistence or reappearance of blood microfilaria in another two. Conclusions Due to increasing travel and the migration of people from the endemic countries of West Africa to Europe and the USA, we speculate on the possible emergence of loiasis. Western physicians should be aware of the typical (eye worm migration and Calabar swellings) as well as unusual clinical presentations