Microsporidia infection in patients with the human immunodeficiency virus and unexplained cholangitis

BACKGROUND

Cholangitis in patients with the acquired immunodeficiency syndrome (AIDS) is usually associated with opportunistic infections by cryptosporidium species or cytomegalovirus, but in about a third of cases no opportunistic agent is identified. We suspected some of these cases of biliary disease might be explained by infection with the microsporidia species Enterocytozoon bieneusi, an obligate intracellular protozoan that causes chronic diarrhea in patients infected with the human immunodeficiency virus (HIV).

METHODS

We studied eight HIV-infected homosexual men (in either group IV of the classification of the Centers for Disease Control and Prevention or group II, with a CD4 cell count of < or = 10 per cubic millimeter) who were referred because of cholangitis for which no causative agent had been found by standard tests. All the patients underwent abdominal ultrasonography and endoscopic ultrasonography or endoscopic retrograde cholangiopancreatography with collection of bile from the common bile duct. One patient had transhepatic biliary catheterization, and two others had cholecystectomy. Bile samples, duodenal- and liver-biopsy specimens, and gallbladder tissue were studied by light and electron microscopy.

RESULTS

All eight patients with unexplained AIDS-related cholangitis had biliary microsporidosis. Intraepithelial E. bieneusi spores (1 to 2 microns) and supranuclear plasmodia (3 to 8 microns) were identified in the six duodenal-biopsy specimens. May-Grünwald-Giemsa staining of bile samples revealed free forms of microsporidia in all eight patients, and the presence of E. bieneusi was confirmed by electron microscopy. E. bieneusi was also identified in ductal biliary cells on a liver biopsy, in one common-bile-duct smear, and in gallbladder epithelium (in two patients). Four patients were found to have associated but previously undetected biliary or duodenal cryptosporidiosis, whereas another had biliary infection associated with cytomegalovirus.

CONCLUSIONS

Infection of the biliary tract with E. bieneusi is associated with and may be a cause of AIDS-related cholangitis.

Enterocytozoon bieneusi infection in acquired immunodeficiency syndrome-related sclerosing cholangitis

Acalculous cholecystitis and sclerosing cholangitis due to Cryptosporidium sp, and cytomegalovirus have been described in patients with the acquired immunodeficiency syndrome (AIDS). However, in about 40% of cases of AIDS-related biliary disease, no opportunistic pathogen is identified. The current case report describes the first case, to the best of the authors' knowledge, of AIDS-related sclerosing cholangitis associated with microsporidiosis. Enterocytozoon bieneusi was detected in the duodenum and bile by means of light microscopy and confirmed by electron microscopy. Microsporidian infection should be suspected in patients with AIDS-related sclerosing cholangitis as well as in cases of diarrhea in which none of the usual pathogens are found.

Evaluation of a rapid enzyme immunoassay for diagnosis of hepatic amoebiasis

We compared the capability of rapid enzyme immunoassay (EIA) to detect antiamoebic antibodies during hepatic amoebiasis with those of indirect hemagglutination and latex agglutination. EIA is simple to perform and rapid (20 min) and does not require any special equipment (optical reading is sufficient). EIA of 143 sera (including 43 from patients with proven hepatic amoebic abscess, 33 from patients with other hepatic disorders and/or parasitic infections, and 67 from healthy individuals) yielded a specificity, a sensitivity, and positive and negative predictive values of 100, 93, 100, and 97.1, respectively. This test could thus be considered another valuable tool for the diagnosis of hepatic amoebiasis.

[Combined infection with HTLV-1 and Strongyloides stercoralis]

Infection of carriers of strongyloides by the human oncogenic retrovirus HTLV-1 significantly augments the number of larval parasites in the stools and impairs the action of anti-helminthic agents, resulting in an increase in immediate and longer term failure of therapy. The proliferation of cytokine type 1 secreting lymphocytes, the preferred target for viral infection, shifts the Th1/Th2 balance in favour of a Th1 response with a consequent increase in the production of gamma interferon (INF-γ). In addition to other effects, this causes a decrease in the secretion of cytokines IL-4, IL-5 and IL-13, which results in substantial reduction in total and specific IgE; failure of activation of eosinophils or stagnation in or reduction of their numbers; and an increased risk of development of a severe form of strongyloidiasis. This risk is clearly correlated with the level of anti-HTLV-1 antibodies and the amplitude of the proviral load of peripheral lymphocytes. The polyclonal expansion of infected CD4 cells might be partly due to the activation of the IL-2/IL-2R system by parasite antigens together with the action of the virus type 1 Tax protein. The fact that adult T cell leukaemia arises significantly earlier and more often in individuals with combined infection is an argument in favour of the parasite's role as a leukaemogenic co-factor. In practice it is, therefore, appropriate to initiate all available measures to eliminate parasites from co-infected hosts although this does present difficulties, and one should not reject the possibility of a diagnosis of strongyloidiasis in the absence of hypereosinophilia. In all cases of chronic strongyloidiasis without hypereosinophilia, co-infection with HTLV-1 should be looked for routinely. The same applies to carriers of strongyloides with repeated treatment failures. Finally, corticosteroids and immunosuppressants should be used only with care in HTLV-1-positive patients who seem not to be co-infected, even if they have received precautionary therapy.

Threats to the Effectiveness of Malaria Treatment

In reaction to the speed and ease with which a high level of resistance against P. falciparum was induced in vivo in a mouse NOD/SCID IL-Ry^-/- model by sub-therapeutic doses of artesunate [2], this text begins a plea for concrete measures to limit the risk of eventually appearing the same phenomenon in the field, including a strengthening of the fight against the use of artesunate oral monotherapy, tablet often under-dosed or artemisinin herbal tea and the adoption of more reliable and more efficient means than those currently used to detect the emergence of resistance earlier and a relaunch of the search for new antimalarials.

[A mosquito net for everyone in 2010]

At less than two hundred days of the 2010 deadline for the "Roll Back Malaria" initiative which committed itself to reduce by half, before that date, mortality due to malaria in the world and relying on the latest WHO reports pointing out, in Africa, major shortcomings concerning the accessibility to treatment combinations consisting of artemisinin and on the acknowledged fact that an insufficient number of pregnant women receive an intermittent treatment, the author notes that a coverage, so-called universal, with the use of long action insecticide treated mosquito nets has become the Grail of the battle against malaria, with the perverse effects entailed, namely that of blinding realities or throwing discredit on other types of possible interventions that are not consistent with an accounting logic. He also notes that the average figure of estimated deaths due to malaria was at a quasi stagnation in 2008 and that the lives of 34,000 African children of less than 5 years of age saved between 2006 and 2008 was achieved in the context of the reduction in infant mortality resulting from a series of causes among which it is impossible to individualise malaria with certainty. He finally points out that Eritrea, Rwanda, Zambia, São Tome y Principe and the Tanzanian island of Zanzibar which quite regularly serve as showcases to RBM and UNICEF and which report spectacular progress in the field of prevention of malaria accompanied by a parallel reduction in its mortality, are, for different reasons, far from being representative of the totality of African countries and that they should be considered as exceptions rather than examples to be exploited without restraint. On the other hand, the author considers that deluding the grand public into thinking that a few watchwords, slogans and simple, even simplistic, ideas would enable eradicating malaria given that large sums of money are made available, is not quite honest and may finally prove to be dangerous. He warns against the false hopes concerning the impact of coming discoveries on the antimalarial battle often conjured up to take over today's actions, by recalling that a century of scientific, technological and medical progress has not positively translated into any decisive progress in the prevention or treatment of this disease, in spite of the issue of scientific publications on the subject at every 20 minute interval since more than thirty years. Although the author willingly agrees that huge financial means are essential and for a long time to come, he however believes that they would not suffice to enable, in countries with high rates of transmission, the elimination of a disease that is not solely linked to biological, ecological and entomological parameters, but that is also anchored to the economic, societal, social and cultural contexts that are quite often forgotten and on which it is difficult, but essential, to act in order to obtain long lasting results. He recalls, on this occasion, that man, as an individual in relationship with his surroundings, should also be at the heart of the battle on the same footing as the anopheles and the plasmodium, even if this, at times, leads to clashes between medical logic and native social, traditional, popular, scholarly or religious logics. He regrets, similarly and within the spirit of the Abuja declaration, that the educational systems of African countries having a high transmission rate do not play the role they had to assume in the battle against malaria and are not mobilised much better than they are, by including, for example, in the primary and secondary curriculum of public and private schools, on the same footing as the learning of the alphabet or of the multiplication tables, a compulsory adapted instruction in malaria, so that children not only become victims but also "actors in the battle against malaria". The author finally underlines the absolute necessity to rapidly strengthen health care facilities of the most affected countries, particularly in the rural area, and plead that this intensification becomes a true priority financed on its own merits. The Global Malaria Action Plan, that will take over from the RBM and would have the advantage of masking the insufficient results obtained by the latter, would have to face two huge challenges: an ancient but recurring one that concerns, in the context of a world economic crisis, the financing of the battle against malaria and the other one, new and associated with the development of resistance by Plasmodium falciparum to artemisinin, a first- and last-line antimalaria drug.

[Chagas Carlos Justiniano Ribeiro (1879-1934)]

The story of the life of Carlos Chagas is closely associated with the discovery of American Human Trypanosomiasis, caused by Trypanosoma cruzi. Indeed, he worked on this for almost all of his life. Nowadays he is considered as a national hero, but, when he was alive, he was criticised more severely in his own country than elsewhere, often unjustly and motivated by jealousy, but sometimes with good reason. Cases of Chagas disease in non-endemic countries became such a concern that public health measures have had to be taken. In this article we give a short account of the scientific journey of this man, who can be said to occupy his very own place in the history of Tropical Medicine.

[Human American trypanosomiasis 90 years after its discovery by Carlos Chagas. II--Clinical aspects, physiopathology, diagnosis and treatment]

Cardiac, neurologic, and gastrointestinal manifestations of Chagas Disease have been well documented, but underlying pathophysiologic mechanisms, especially of chronic myocarditis, remain unclear. In the last decades, vectorial and transfusional transmission has been diminished. However congenital forms, which were long unknown and are still poorly understood, and reactive forms, which occur in patients with acquired or induced immunodeficiency, have confounded conventional wisdom concerning the evolution of this disease. Several new diagnostic tools have been developed without replacing the traditional methods, e.g. the xenodiagnostic technique proposed by Brumpt. With regard to indirect diagnosis, further progress is needed to improve specificity and sensitivity as well as the discriminating ability of the numerous techniques now available. Recently several double-blind randomized trials showed that benznidazole may be useful for early stage disease in children under 12 years of age. Further study with long-term follow-up will be necessary to determine the value of generalizing treatment to all patients with Chagas disease regardless of age and disease stage. However the ideal trypanocidal agent has yet to be found. Although attempts to immunize animals have not been complete failures, current results are not adequate to hold forth hope of a vaccine for use in man within the foreseeable future.

[Polyresistance of asiatic P. falciparum to chloroquine and pyrimethamine-sulfadoxine combination. Apropos of a new case]

The authors report a case of a multi-drug resistant Asiatic P. falciparum strain in a first non-immune man treated out of an endemic zone after failure of chemoprophylaxis by pyrimethamine-sulfadoxine. The authors compare this care with the lately published cases in Germany and Switzerland. They call again that I and II resistances were observed at the time of the drug's trials in and out of endemic zones. They ascertain that this resistances are often associated with chloroquino-resistance and that their number increases chiefly in certain areas.

[Reflections on Three Episodes of Louis Pasteur's Life as Seen in the William Dieterle's Movie (1936)]

Despite the criticism and reservations made about him still nowadays, Louis Pasteur may be considered one of the most important scientists of the last two centuries in public health, even if the work of the numerous scientists who preceded him have largely contributed to the successes he obtained without following too much to the rules of deontology and ethics currently in force in the world of research and medicine. He has definitively put down, by his experiments, the "theory of spontaneous generation" in force since antiquity, validated that of "germs or microbes", enacted the first rules of asepsis, while inspiring those of the antisepsis applied by Joseph Lister, and developed a certain number of vaccinations in veterinary and human medicine, including the anti-rabies, the one which made him famous all over the world. All this was not done without difficulty and Pasteur encountered for a large part of his life the misunderstanding of his contemporaries and the hostility of the medical world to which he did not belong. The authors comment in this text the movie The Story of Louis Pasteur by William Dieterle, filmed in 1936, based on the knowledge acquired since that date and doing the part of the real and the fiction.

A comparative approach to the French medical missions in Brazil and in sub-Saharan Africa before the Second World War

Franco-Brazilian cooperation in the field of microbiology and tropical diseases dates back to the onset of those disciplines. Physicians were sent over by France, namely Marchoux, Simond and Salimbeni from 1901 to 1905 to study yellow fever, and Emile Brumpt from 1913 to 1914 to teach parasitology. These missions brought in some important results. After confirming that the yellow fever agent was a filterable virus and that Stegomya (Aedes) its only vector, Simond and Marchoux clarified the biology of the mosquito and showed that sexual transmission of the virus could occur. They also set up different measures for the control of yellow fever outbreaks which Oswaldo Cruz was inspired by for his campaign against yellow fever. Emile Brumpt implemented the teaching of parasitology at the Faculty of Medicine in São Paulo and contributed to human American trypanosomiasis by defining the transmission of the disease and the cycle of the parasite responsible for it. He also developed the technique known as xenodiagnosis. Simond and Marchoux's works on yellow fever found an immediate application in French colonies, particularly in sub-Saharan Africa. However, the fight against large African endemics such as sleeping sickness, the other human trypanosomiases, could not have been carried out successfully without the contribution of mobile teams following Eugène Jamot's initiative in addition to the permanent centres which characterized the French colonial system.

[American human trypanosomiasis 90 years after its discovery by Carlos Chagas. I. Epidemiology and control]

It was in 1909 that Carlos Chagas described the disease which now bears his name. During the ensuing 90 years, our knowledge of this apparently whimsical, protozoan disease has grown enormously but many points remain unclear. Epidemiologically speaking, current knowledge is poor about the mechanisms and markers of variability of Trypanosoma cruzi, mechanisms allowing the organism to survive in the host, and susceptibility of infected individuals to disabling or fatal late complications. With regard to vector control, it is increasingly obvious that success will be more difficult than previously thought due to the likelihood that, as domestic species are exterminated, they will be replaced by semi-domesticated or wild species. Two other factors that have significantly changed the conventional epidemiological profile of Chagas'disease on the subcontinent over the past 50 years are human intervention in the environment and population migration from rural to urban zones. Despite the breakthroughs achieved in the last decade. Chagas'disease, with its multiple modes of transmission (vector-borne, congenital, and transfusional to name but the most important), diverse reservoir involving over 175 species, and potential for course of the disease in man, will remain a major health problem in Latin America countries for many years to come.

[Characterisation of the exoerythrocytic stage of the asexual cycle of the human plasmodia: a painstaking process]

The difficulties encountered in the discovery of the exoerythrocytic stage of the asexual cycle of the human plasmodia are described. These illustrate how deference towards scientific orthodoxy and a degree of reluctance to question and to criticize can delay advances in knowledge.