Utility of an internal control for the polymerase chain reaction. Application to detection of Mycoplasma pneumoniae in clinical specimens.

The polymerase chain reaction (PCR) was used to amplify a 209 base-pair fragment of Mycoplasma pneumoniae DNA. The amplicon was transferred into a plasmid and a 680 base-pair piece of foreign DNA was inserted between the two amplimer sites. Plasmid DNA was added to the reaction mixture as an internal control for the polymerase chain reaction. Since the original hybridization target sites were included in this construction, one pair of amplimers could be used to amplify both the target DNA and the internal control DNA. Separation of internal control from target DNA after amplification was easily obtained on agarose gel electrophoresis. For the analysis of clinical samples with the polymerase chain reaction, the addition of internal control DNA allowed monitoring of the overall effectiveness of the amplification in each tube. With this technique approximately one-third of the tests were shown to be unsatisfactory due to technical errors or contaminating inhibitors. Adequate internal controls are necessary to avoid false-negative results with the polymerase chain reaction.

Detection of herpes simplex virus in the cerebrospinal fluid of patients with encephalitis using the polymerase chain reaction.

Herpes simplex encephalitis is a neurologic emergency demanding immediate institution of specific therapy in order to prevent mortality. Diagnosis, however, is a complex matter with controversy existing over the appropriateness of brain biopsy. We report the demonstration of herpes simplex virus DNA by means of the polymerase chain reaction (PRC) in the cerebrospinal fluid of 3 patients with herpes simplex encephalitis. One of the patients suffered from brain-stem encephalitis with high intensity signals in the pons on magnetic resonance imaging, the second reported case of this entity. The PCR for herpes simplex on a control series of cerebrospinal fluid of 20 patients with other central nervous system infections was negative. PCR of cerebrospinal fluid offers a sensitive, specific and rapid diagnosis of herpes simplex encephalitis, making brain biopsy unnecessary. Still, the importance of strict measures to prevent contamination cannot be stressed enough. It is possible that due to the high sensitivity of the PCR, herpes simplex may be found in other infectious syndromes of the central nervous system.

Characterization of some ungrouped viruses.

Bangui, Bobaya, Kowanyama, Upolu and Zinga are enveloped spherical RNA viruses sensitive to ether and acid pH; morphologically resembling Bunyaviridae, their diameters range from 90 to 100 nm and their bouyant density is 1.17 to 1.18 g/ml in sucrose. St. Floris, a bunya-like virus, serologically related to Rift Valley Fever, has a diameter ranging from 90 to 110 nm. Triniti, Zingilamo, IPYM 120 and virus strain AnB4268 are enveloped spherical RNA viruses sensitive to ether and acid pH, have diameters of 65, 55, 55 and 60 nm and bouyant densities of 1.18, 1.24, 1.20 and 1.18 g/ml in sucrose, respectively; morphologically they resemble Togaviridae. Salanga is a poxvirus measuring 190 X 225 nm. Virus strain AnY1444 is a spherical, non-enveloped RNA virus measuring 85 nm, morphologically resembling Reoviridiae; it is restraint to both ether and acid pH and shows two-peak densities of 1.32 and 1.36 g/ml in caesium chloride. Bangoran, Keuraliba and Yata resemble Rhabdoviridae measuring 60 X 175, 65 X 195 and 60 X 185 nm, respectively.

Congenital pneumonia due to Mycoplasma pneumoniae.

A case of probable vertical transmission of Mycoplasma pneumoniae is presented. The presence of M pneumoniae was demonstrated by the polymerase chain reaction (PCR) in the nasopharyngeal aspirate of a newborn who developed pneumonia shortly after birth. This result was confirmed by performing a second PCR, amplifying another part of the genome of M pneumoniae. It is concluded that M pneumoniae can be added to the long list of pathogens known to cause congenital pneumonia.

Ambulatory treatment of multibacillary leprosy with a regimen of 8 months duration.

An ambulatory treatment regimen for multibacillary leprosy, of 34 weeks duration composed of 8 weeks daily supervised rifampicin, ethionamide (ETH), dapsone (DDS) and clofazimine (CLO) followed by 26 weeks of unsupervised ETH, DDS and CLO, introduced in 1983 has been evaluated; 268 patients were followed for a mean of 4.4 years and a total of 1188 patient years. The relapse rate was 0.33 per 100 patient years of follow up. The reduction of the duration of the combined administration of RMP + ETH reduced the hepatotoxicity to 1.4%. It is possible that both phases of the regimen studied could still be reduced, however, in the near future ETH will be replaced by alternative bactericidal drugs, avoiding the hepatotoxicity.

Combined regimens of one year duration in the treatment of multibacillary leprosy--I. Combined regimens with rifampicin administered during one year.

In 1981, 1982 and 1983, 216 multibacillary patients in Anjouan (Comores) and Burundi were treated for 8 weeks with daily rifampicin (600 mg) ethionamide (500 mg) and dapsone (100 mg) or clofazimine (100 mg) followed for 44 weeks by once weekly rifampicin (600 mg) and daily ethionamide (500 mg) and dapsone (100 mg) or clofazimine (100 mg). There were 109 previously untreated patients and 107 patients who had dapsone monotherapy, 16 of whom were infected with proven dapsone resistant Mycobacterium leprae. Clinical and bacteriological results were excellent but hepatotoxicity of this regimen remains a problem. No relapses were observed during a 2 to 6 years (mean: 4.29 years) follow-up period after the end of treatment (upper 95% confidence limit of 0.40 per 100 persons years). It is concluded that multibacillary leprosy can be successfully treated with a regimen of one year duration, but less toxic regimens, more easily applicable in the field, are necessary.

Combined regimens of one year duration in the treatment of multibacillary leprosy--II. Combined regimens with rifampicin administered during 6 months.

From 1981 to 1983 all multibacillary patients presenting at the collaborating centres in Zaire and Rwanda were treated with one of the following regimens: 6 months supervised daily RMP 600 mg, ETH 500 mg and DDS 100 mg or CLO 100 mg followed by 6 months unsupervised daily DDS 100 mg or CLO 100 mg with ETH 500 mg added or not. These regimens gave rise to hepatotoxicity, reversal and erythema nodosum leprosum reactions as described previously. Bactericidal activity was excellent. Among the 289 patients in the trial, with a mean follow-up period of 3.88 years, no relapses were observed, with an upper 95% confidence limit of 0.35 per 100 person years. Because of the hepatotoxicity, alternative short-course therapies need to be tested.

Evaluation of five treatment regimens, using either dapsone monotherapy or several doses of rifampicin in the treatment of paucibacillary leprosy.

The objective of the present study was to define short-course treatment regimens for PB leprosy and to compare them with the 'classical' dapsone treatment and the WHO-PB regimen. Five treatment regimens were studied and evaluated by the histologic evolution. The regimens were: (1) dapsone 100 mg daily, non-supervised for 3 years; (2) RMP 900 mg supervised, once weekly, 8 doses; (3) idem 12 doses; (4) RMP 600 mg, once monthly, supervised, 6 doses and during this treatment dapsone 100 mg daily unsupervised; (5) RMP 600 mg together with dapsone 100 mg daily, supervised for 6 days. For each of these regimens there were between 114 and 195 person-years of follow-up. Results are comparable for the 5 treatment regimens, and reach 65-75% cure rates at 36 months and 80-90% at 48 months after the start of therapy. The relapse rate for all groups is about 0.5% per year. The difficulty for the diagnosis of relapse in PB leprosy is discussed. It is concluded that treatment of PB leprosy can be relatively simple but that a relatively long time is needed to evaluate its effect.

Treatment of multibacillary leprosy with a regimen of 13 weeks duration.

In a prospective study 559 multibacillary patients in Zaire were treated for 13 weeks with twice weekly rifampicin (600 mg) and daily ethionamide (500 mg) and dapsone (100 mg), 13-RED, or clofazimine (100 mg), 13-REC. The patients were followed for a total of 1418 person years, mean 3.2 years. The incidence of hepatitis was 3.3%. The incidence of relapses was 0.28 per 100 person years. Relapses were due to drug-sensitive organisms. In patients who received the same drug regimens but with a reduced dosage of ethionamide to 5 mg/k bodyweight, the incidence of hepatitis was significantly lower but the relapse rate was 7.8 per 100 person years of follow-up in the RED group, no relapses were diagnosed in the REC group. It is concluded that by the use of potent antileprosy drugs in suitable combinations and dosages, it will be possible to shorten the duration of antibacterial treatment in multibacillary leprosy to 3 months.

A controlled therapeutic trial in paucibacillary leprosy comparing a single dose of rifampicin with a single dose of rifampicin followed by one year of daily dapsone. The Collaborative Study Group for the Treatment of Leprosy in Zaire.

The cure rates of two treatment regimens in PB leprosy were compared in a prospective randomized trial: treatment U consisting of a single dose of rifampicin 40 mg/K bodyweight, and treatment A of rifampicin 1500 mg in a single dose, followed by one year of daily dapsone 100 mg. In patients with a BI = 0, the cure rates evaluated on the basis of histopathology of skin biopsies, were identical for the two regimens but in patients with a BI = 1, cure and relapse rates were unacceptable. For this reason and particularly the need to separate patients on the basis of the BI in skin biopsies, the single dose regimen does not appear to be suited for wide-scale application.

A randomized clinical trial of two single-dose treatments for paucibacillary leprosy.

We compared 2 single-dose regimens for the treatment of paucibacillary leprosy in a randomized clinical trial in Zaïre. The regimens were: C2 (rifampicin 40 mg/kg and 1200 mg clofazimine once) and C4 (rifampicin 40 mg/kg, clofazimine 100 mg, DDS 100 mg and ethionamide 500 mg once). An analysis of the results of patients enrolled between May 1987 and December 1988, with a maximum follow-up of 4 years, is presented. A total of 622 patients were enrolled and 14 paucibacillary and 1 multibacillary relapses occurred. The overall paucibacillary relapse rate was 2.4 per 100 person years. This relapse rate was higher for older patients as well as for patients with 3 or more lesions. The probability of cure at 3 years is 0.816 for C2 and 0.823 for C4, the difference not being statistically significant. The probability of cure at 3 years with either regimen is higher for patients with 1 or 2 lesions (0.872) than for patients with 3 or more lesions (0.787), and it is higher for patients with a bacterial index of 0 (0.831) than for patients with a bacterial index of 1 (0.699). These results are compared to other studies. We also discuss the potential of single-dose treatment regimens for paucibacillary leprosy.

Classification of leprosy cases under field conditions in Bangladesh. I. Usefulness of skin-smear examinations.

In 2 non-governmental organization projects in Bangladesh 244 new leprosy patients were classified in the field according to clinical criteria. Skin smears were taken at 4 standardized sites and at the most active peripheral lesion, where a biopsy was also taken. Comparison of the clinical field classification with the results of the skin smears and biopsies gives a sensitivity of 92.1% for the clinical criteria, but a specificity of only 41.3%. The skin-smear results, on the other hand, have a sensitivity of 88.4% and a specificity of 98.1%. Thus, skin smears may contribute considerably to the operational classification of leprosy patients under field conditions. Quality control of the peripheral laboratory is essential. Appropriate site selection for the smear taking will also contribute to increased performance. Analysis of the skin-smear results suggests that the policy of taking smears at standardized sites should be abandoned in favour of the earlobes and active peripheral lesions.

Classification of leprosy cases under field conditions in Bangladesh. II. Reliability of clinical criteria.

In 2 non-governmental organization projects 244 new leprosy patients in Bangladesh were classified in the field according to clinical criteria i.e. number of skin lesions and number of enlarged nerves. Comparison of these classification results with the results of skin smears and biopsies yielded a sensitivity (for detection of a MB case) of 92.1%, but the 'unconfirmed MB rate' amounted to 52.6%. In order to improve the reliability of the operational classification, several additional clinical criteria were investigated. It was found that neither the presence of anaesthesia in the skin lesions nor the presence of grade 2 disabilities or peripheral anaesthesia or voluntary muscle testing (VMT) impairment contributed to an improved classification. Counting the number of body areas showing signs of leprosy, which had proven very useful in other programmes, did not result in a more reliable classification in the 2 projects in Bangladesh. The presence of clinical signs of lepromatous leprosy, more specifically nodules or diffuse infiltration, could be a useful addition to the classification criteria. If the sensitivity must remain higher than 90%, the lowest 'unconfirmed MB rate' obtainable in Bangladesh, using clinical criteria only, is 46.4%, for a sensitivity of 91.0%. However, the inclusion of skin-smear results in the classification criteria could improve the sensitivity to 96.6% and lower the 'unconfirmed MB rate' to 40.3%. A reduction in MB overclassification will result in more efficient and more cost-effective leprosy control programmes.

Monkeypoxvirus infections.

During and after the smallpox eradication campaign, human cases of monkeypox appeared in West and Central Africa, as isolated cases or as small epidemics. Since inter-human transmission has never or only very exceptionally been documented, monkeypox does not represent a serious threat to humans. The virus reservoir is among tree squirrels living in the tropical rain forests of Africa and humans are infected by hunting, killing and skinning these animals. However, the modernization of society lessens human contact with the virus reservoir. Since the eradication of smallpox, stocks of variola virus have been maintained; whether these stocks should now be destroyed is a political question, which is seriously compromised by mistrust between countries.

Molecular biology in diagnostic microbiology. PCR on Mycobacterium leprae.

The polymerase chain reaction (PCR) has already produced several hundreds of papers. Alternative procedures for diagnostic purposes based on nucleic acid detection do exist but have until now found less application. Problems with the PCR are discussed. It is proposed that the diagnostic microbiology laboratory has a section devoted to PCR for the diagnosis of diseases whose etiologic agent can "almost not" be cultured such as (for Flanders) Mycoplasma pneumoniae, Chlamydia pneumoniae, Toxoplasma gondii, EB virus and some other agents in particular specimens. In this setting the PCR would only be performed on selected, clinically justified samples, in close collaboration between clinician and microbiologist. PCR will evidently play an important role in research. Illustration is given of PCR applied for the detection Mycobacterium leprae.

Therapeutic regimens in leprosy.

Insight into the bacteriology, general pathology, pharmacology of the treatment of leprosy has increased most significantly during the last 30 years, through numerous studies, starting with the demonstration by Shepard, of the multiplication of Mycobacterium leprae in the mouse foot pad. Our studies showed that the treatment of the disease can be considerably shortened. The introduction of more drugs, highly bactericidal for M. leprae, provided toxicity and antagonism do not constitute a problem, can only improve the results in terms of length of treatment and absence of relapses. Only when the public realizes that leprosy can indeed be treated "like any other disease" will the fear for it decrease, will patients show up in earlier stages of the disease, will transmission and endemicity decline and will a situation be reached comparable to that of tuberculosis in the western world. In the meantime there is an increasing need for better understanding, prevention and treatment of the complications of the disease: reversal reactions and erythema nodosum leprosum. In endemic regions there will remain for some time to come a great need for rehabilitation activities.

[Infectious diseases, the veritable pandora's box]. / Infectieziekten, de onuitputtelijke doos van pandora.

The past few years, much attention has been given to the problems regarding new and emerging infectious diseases. Four groups may be considered: (1) new agents discovered among the causes of classical medical syndromes, these do not constitute new dangers but decrease the proportion of unknown causes within these syndromes; (2) increased importance of infectious agents resulting from modified ways of living or production procedures; (3) the really new agents, the spread of which is generally favoured by the same factors and (4) organisms with acquired resistance against antibiotics and pesticides. There is need for extended epidemiological surveillance, that can be improved in our country by better collaboration between different organisations. Most importantly epidemiological surveillance should be organized on an European level with the entire support of our regional and federal authorities.

[To live happily, we live secretly. The knowledge of virus reservoirs is essential for the fight against infectious diseases]. / Pour vivre heureux, vivons cachés (J.P. Claris de Florian) de kennis van de virusreservoirs is essentieel bij de bestrijding van infectieziekten.

The concept of virusreservoir is defined and illustrated. It corresponds to the site where the microorganisms survive "cachés et heureux". The definite control of infectious diseases consists, whenever possible, of the elimination of the responsible organisms from their reservoir. Frequently the virusreservoir was originally thought to be located in the proximity of man, but later investigations showed many reservoirs to be situated at much greater ecological distance. In many situations the phenomenon of latency plays an important role. This phenomenon is badly understood and a better understanding of its mechanisms could offer means to combat the microorganisms and the diseases they cause.

[Yersinia pestis. Bacteriology]. / Yersinia pestis. Bacteriologie.

The author discusses the evolution in the classification of the bacterium, responsible for plague: first a classification based on phenotypic characteristics, later based on genotypic characteristics, to finally arrive at an evolutionist classification. He treats the seven species of the genus Yersinia that can be distinguished by DNA hybridization. He examines the issue of sequencing and decoding the chromosome and mentions research regarding the phenomenon that the metabolism of the organisms modifies as a reaction to signals of their changing environment. Furthermore the author discusses the efforts to characterize the strains of Y. pestis (antiqua, medievalis and orientalis). Finally he comments on the discovery of a multiresistant strain, isolated in 1995 in Madagascar.

[Plague in Zaire]. / Pest in Zaire.

Two endemic foci of plague have been discovered in Zaïre, the first in the Ituri in 1928, the other in North-Kivu in 1938. They are situated in the region of the great East-African Rift and are adjacent to the Ugandan focus, identified in 1877. A strict surveillance of these endemic foci makes it possible to state that, between 1928 and 1959, 632 cases of plague have been diagnosed in the Ituri, or 20 a year, and 190 in the N-Kivu, or 8 a year. Since then several flare ups have been notified. This situation is very remote from the "black death" concept. Yersinia pestis presents, besides its bipolar staining, many other characteristics such as the indispensable presence of iron to produce virulence, or the fermentation of glycerine and reduction of nitrates as parameters for the identification of 3 biovars, corresponding with a specific geographic distribution: antiqua, medievalis, orientalis or maritima. The antigenic structure has been discussed and also the role of plasmids. Plague is a disease of rats, a variegated gathering of rodents with different degrees of tolerance and sensitiveness to Y.pestis, living in a frail equilibrium. The multimammate houserat was in the Ituri the principal agent until the black rat Rattus rattus invaded the region and a new balance came into being. The frequent changes in taxonomy of Mastomys caused uncertainties. The transmission is due to fleas subject to a blocking of their ventriculum by Y.pestis. Fleas play an active part in the process. Man is only a casual intruder. The pathogenicity is related to its invasiveness and its intracellular localization in macrophages and other R.E. cells, in which Y.pestis can survive. The bubo is characteristic of the disease. In Zaïre a septicaemic tendency has been observed, with a possible involvement of the C.N.S. and of the lungs. The latter may produce among the surrounding relatives primary pneumonic plague. The clinical diagnosis ought to be confirmed by bacteriologic investigation of the puncture fluid of the bubo, the blood, and when necessary the C.S.F. or the sputum by culture and/or animal inoculation. The treatment became very efficient since the availability of sulfamides and later antibiotics: aminoglycosides, chloramphenicol, tetracyclines. A timely administration ensures practically recovery. As soon as Y.pestis was identified vaccination was put into practice and in the first place by killed germs (Haffkine's lymph) to day with formalized F1, for mass vaccination live attenuated strains were used: Tjiwidej (Otten), E.V. (Girard), K120 (Grasset).(ABSTRACT TRUNCATED AT 400 WORDS)