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Our group previously reported a strong familial clustering of HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in Zaire, suggesting a familial transmission of the virus together with the presence of cofactors. In the present study among 84 relatives of 16 HTLV-I-positive or HAM/TSP index cases, we found that all 15 seropositive children had a seropositive mother and that all 15 children with a seropositive father but a seronegative mother were seronegative. Lymphocytes of 17 relatives from 2 families with a familial HTLV-I-associated neuropathy were tested in 2 polymerase chain reaction (PCR) assays amplifying pol and tax/rex gene fragments. The 10 seropositive individuals were PCR positive for HTLV-I and the 7 seronegatives were negative in both PCR assays. The PCR results showed no evidence for a long lag period between infection with HTLV-I and seroconversion. The HTLV-I long terminal repeat (LTR) of these 10 individuals, related in the first to the fourth degree, was amplified and sequenced. Identical sequences were found within the families except for one woman infected with two variants, one being the familial strain and the other a mutated one with a single nucleotide substitution in the 755 sequenced nucleotides of the LTR region. The family strain and the mutant were both present in two samples taken 1 year apart. Together, the HTLV-I serology, PCR, and sequencing results point toward mother-to-child transmission as the main mode of HTLV-I infection in this population. Comparison of the LTR sequences of the two families with other HTLV-I strains from different geographical regions shows that the Zairean HTLV-I strains form a separate cluster.(ABSTRACT TRUNCATED AT 250 WORDS)

Due to the low evolutionary rate and the limited horizontal transmission of human T-lymphotrophic virus type I (HTLV-I), its phylogenetic analysis reveals the movements and contacts of ancient populations. Since simian strains cannot be distinguished from human strains by phylogenetic criteria, this virus has appropriately been called primate T-lymphotropic virus type I (PTLV-I). We sequenced the LTR of six PTLV-I strains: three HTLV-I strains from African patients with tropical spastic paraparesis (TSP) (Equateur, Zaire), two laboratory HTLV-I strains of Japanese origin, MT-2 and MT-4, and one STLV-I from a baboon of the primate center in Sukhumi, Georgia. We applied four phylogenetic inference methods: neighbor-joining (NJ), unweighted pair group method using arithmetic averages (UPGMA), Fitch and Wagner parsimony (pars), and maximum likelihood (ML), to these 6 LTR sequences and 18 published LTR sequences (cosmopolitan, African, and Melanesian HTLV-I strains and African and Asian STLV-I strains). Three major HTLV-I subtypes can be identified with all four methods: the cosmopolitan HTLV-Ia, the central African HTLV-Ib, clearly descendant from a STLV-I CH-like African ancestral simian strain, and the Melanesian HTLV-Ic, probably descendant from an Asian STLV-I strain. We observe a segregation of PTLV-I sequences according to their geographical origin and not according to host species. The Zairean strains form a cluster closely related to an STLV-I strain isolated from a chimpanzee (STLV-I CH) and distinct from western African strains, which belong to the cosmopolitan subtype of HTLV-I. The Sukhumi STLV-I strain found in a captive-born baboon was of Asian descent. We experienced rooting problems with UPGMA when using HTLV-II as an outgroup. Concordant results with all four methods were obtained by eliminating HTLV-II LTR sequence fragments with bad alignment to HTLV-I. This resulted in a HTLV-II root node on the African STLV-I TAN90 terminal branch (with bootstrap values above 92% for the NJ and pars methods) and not on the Asian STLV-I PtM3 branch, as has been derived by others based on their use of UPGMA. The results of the analyses also support a higher evolutionary rate of PTLV-I in Asia, implying that the trees obtained with the NJ and ML methods have a higher reliability. These results are more compatible with an ancient African origin of PTLV-I than with an Asian origin.

Searching for clues to the evolution of the primate T-lymphotropic viruses (PTLVs), which include the human and the simian T-lymphotropic viruses (HTLV and STLV), we have identified another PTLV, which differs sufficiently from the known PTLV-I and PTLV-II types to be designated here PTLV-L. The virus was isolated from a wild-born baboon (Papio hamadryas) from Eritrea. In a cDNA library a 1802-bp-long fragment was identified that extends from the env region, including the complete transmembrane protein gene, to part of the tax/rex gene. Homologies at the nucleotide sequence level of PTLV-L, prototype simian T-lymphotropic virus-PH969, with HTLV-I and -II, respectively, were 62% and 64% overall, 65% and 70% in the env region, and 80% and 80% in the partial tax/rex sequence. In the 5' part of the pX region a significant homology was seen only with HTLV-II (52%). Phylogenetic analysis based on the gene encoding the transmembrane protein indicates that PTLV-L represents a PTLV type with a long independent evolution, longer than any strain within the PTLV-I or PTLV-II groups. The finding of another PTLV type in African baboons is further evidence of the wide variety of PTLV found on this continent. Whether PTLV-L resembles PTLV-I and PTLV-II in the extension of its host range to other primates, including humans, remains to be seen.

The tropical spastic paraparesis (TSP) is a chronic myelopathy, predominant in the tropics, recently known to be of retroviral origin (HTLV-I). This paper aims at delineating the clinico-etiological evolution of this entity. The historical analysis of it showed that the TSP has had, along decades, many different denominations and the discovery of the retroviral origin for some of them has stimulated new paths of research and epidemiological interest in the tropics and Brazil.

Several reports describing outbreaks of hepatitis A in hemophilia A patients transfused with solvent/detergent-treated factor VIII concentrates have raised concern about possible transmission of hepatitis A by these concentrates. We recently witnessed such an outbreak of hepatitis A in 6 hemophilia A patients; review of the clinical data did not disclose any increased risk factor for community-acquired hepatitis A. A case-control study comparing the prevalence of anti-hepatitis A IgG antibodies in hemophiliacs and age-matched controls showed a lower seroprevalence in hemophiliacs. This might be due to passive protection acquired through transfusion of the previously used immunoglobulin-containing cryoprecipitate. The outbreak of hepatitis A could be explained as a catch-up phenomenon linked to the loss of passive protection with the use of purer factor VIII concentrates.

The drug sensitivities of human immunodeficiency virus type 1 (HIV-1) isolates from a group of four untreated and seven TIBO R82913-treated patients were determined in a reverse transcriptase (RT) assay. Five of the treated patients harbored HIV-1 isolates with R82913 sensitivity comparable to that of the isolates of untreated patients, ranging from almost 2-fold higher sensitivity to 13-fold lower sensitivity than that of recombinant p66 RT. From one of the seven treated patients, an HIV-1 strain with a 20-fold reduced sensitivity to R82913 could be isolated; and from another patient, a strain with 100-fold reduced sensitivity (resistance) was isolated. The drug-resistant strain in this patient emerged after 3 weeks of treatment and was due to the Y188L mutation in its RT. On passaging the virus in cord blood lymphocytes, but not in CEM cells, the resistant virus was lost in favor of a different HIV-1 strain harboring the wild-type Y188 with a sensitivity to R82913 comparable to that of wild-type p66 RT. In several HIV-1 isolates (from treated and untreated patients), some HIV-2- and CIVgab-specific amino acids were found. One of these substitutions, that is, I/V179D (from an untreated patient), conferred a sevenfold reduced RT sensitivity to R82913.

HTLV-II-specific antibodies, with patterns similar to those in the Americas, were present in sera collected about 1970 from Bambuti pygmies in Zaire (14/102; 14%) and from pygmies in Cameroon (5/214; 2.3%), and were more prevalent than HTLV-I. In the Central African Republic, 504 pygmies were HTLV negative. After finding of 4 HTLV-II seropositives among 12 Bambuti pygmies sampled in 1991, this established that HTLV-II or a related retrovirus is present as an ancient endemic in some, but not all, insulated groups of African pygmies, similar to the HTLV-II distribution in Amerindian populations. The endemic among the oldest inhabitants of central Africa, and the occasional and scattered occurrence of apparent HTLV-II among predominant HTLV-I in other Africans, fit well with an ancient African virus and not with importation from the New World. Theories on the origin and evolution of the primate T-lymphotropic viruses (PTLVs) should take into account the longstanding presence of HTLV-II-type viruses in both the Old and New World. Present serology suggests identity of the African viruses with HTLV-II, but their assignment to a new HTLV type is open should genetic analysis show strong divergence from American HTLV-II. Clinical expression, if any, remains to be studied.

Seven patients with decompensated posthepatitis B cirrhosis were treated with low doses of interferon alpha. The initial plasma level of HBV-DNA ranged from 3.0 to 189.3 pg/ml, and that of ALT from 37 to 156 IU/l. Liver biopsies demonstrated ongoing piecemeal necrosis. In sera of all but one patient, HBV-DNA became undetectable by hybridisation techniques within 10 to 28 weeks. Plasma HBeAg became negative in four and HBe-antibodies positive in three patients. Serum transaminase levels showed a marked initial rise 3 to 13 weeks after onset of therapy; they dropped to normal values later in all except one patient. Therapy was initiated at 1 MU (million units) three times a week for 2 weeks and was increased to 2.5 MU for 16 weeks. Later, this dosage was raised to 5 MU three times a week in some patients. Complications included variceal haemorrhage, aggravation of ascites or of encephalopathy, development of pneumonia, recurrence of spontaneous bacterial peritonitis or of gastric ulcer bleeding. One year after stopping the therapy, three patients are well and without any feature of liver decompensation. Three patients died before they could undergo a liver transplantation. In one patient treatment was interrupted because of marked exacerbation of liver cell necrosis. It thus seems possible to suppress HBeAg and HBV-DNA in patients with decompensated cirrhosis. This is important to prepare them for possible liver transplantation. Interferon should be initiated at low doses and the patients be very carefully monitored. Prophylactic therapy for bacterial peritonitis and for variceal haemorrhage is warranted.

In anticipation of systematic prenatal screening at the antenatal clinic of Gasthuisberg University Hospital, Leuven, Belgium, the attitude of 500 successive pregnant women towards testing for rubella, toxoplasmosis, hepatitis B virus, HIV and syphilis was studied by means of written questionnaires. All tests were well accepted, toxoplasmosis and rubella being most (92 and 91%), syphilis and HIV being least (79 and 82%) favoured. Refusal was generally associated with lower education, but refusal for syphilis and HIV was associated with high education. Ninety-four percent wanted to be informed of the results of the tests. Only one woman (0.2%) of those who agreed with testing did not want to know her HIV test result. Pregnant doctors were more reluctant about screening, in particular for sexually transmitted diseases, whereas nurses were in favour of it. Written information failed to increase the acceptance rate, but lowered the number of women without an opinion.

Antibodies to HTLV were determined in 4,630 black African individuals from Zaire, Ghana and South Africa; 185 (4%) were confirmed as seropositive. Seroprevalance was 0.2% in a group of South African women, 0.9% among Ghanaian refugees in Belgium and from less than 1% to over 15% in various sites and populations in Zaire. With the use of HTLV-I and HTLV-II type-specific envelope peptides, 93% of confirmed HTLV seropositives were classified as HTLV-I. Five persons from the Haut Zaire region had HTLV-II serological reactivities, suggesting the presence of HTLV-II or a related retrovirus in central Africa. A cluster of HTLV-I-like indeterminate western blot patterns lacking anti-p24 antibody was found in Bas Zaire.

The following compounds were evaluated for their inhibitory activity against clinical strains of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in both primary rabbit kidney (PRK) and HeLa cell cultures: (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl)adenine (HPMPA), 9-(2-phosphonylmethoxyethyl)adenine (PMEA), (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC), (RS)-9-(3-hydroxy-2-phosphonylmethoxypropyl)-2,6-diaminopurine (HPMPDAP), 5-(5-bromothien-2-yl)-2'-deoxyuridine (BTDU), 5-(5-chlorothien-2-yl)-2'-deoxyuridine (CTDU), 9-(2-deoxy-2-hydroxymethyl-beta-D-erythro-oxetanosyl)guanine (OXT-G), pentosan polysulfate, heparin, dextran sulfate (MW 10,000), acyclovir, 9-(2-hydroxyethoxymethyl)guanine (ACV), (E)-5-(2-bromovinyl)-2'-deoxyuridine (BVDU), 1-beta-D-arabinofuranosyl-(E)-5-(2-bromovinyl)-uracil (BVaraU), vidarabine (9-beta-D-arabinofuranosyladenine) (ara-A) and phosphonoformate (PFA). The most potent inhibitors of HSV-1 were (in order of decreasing activity in PRK cells) BVDU, ACV, BVaraU and OXT-G, their mean 50% inhibitory concentration (IC50) ranging from 0.02 micrograms/ml to 0.9 micrograms/ml. Then followed BTDU and CTDU (IC50 1-2 micrograms/ml), the sulfated polysaccharides (IC50 1.3-5.8 micrograms/ml), the phosphonylmethoxyalkyl derivatives (IC50 5.6-25 micrograms/ml),ara-A (IC50 11 micrograms/ml) and PFA (IC50 38.5 micrograms/ml). Except for BVDU, BVaraU, BTDU and CTDU, the compounds did not discriminate between HSV-2 and HSV-1. All the compounds studied could be considered specific anti-HSV agents. Their selectivity indexes varied from 3 (PFA) to 6400 (BVDU).

A randomized double-blind comparison of five killed hepatitis A vaccine preparations was carried out with eligible medical student and staff volunteers. Vaccines were prepared in M RC-5 cells and formalin-inactivated. Three monthly injections of 1 ml in the deltoid muscle were given. Group A received the CLF strain at a dose of 360 ELISA units (El.U) in 0.5 mg aluminium hydroxide (n = 35). The other groups received the HM175 strain as follows: 180 El.U in 1 mg aluminium hydroxide (to group B, n = 42), 360 El.U in 0.5 mg aluminium hydroxide (to group C, n = 40), 360 El.U in 1 mg aluminium hydroxide (to group D, n = 39) and 720 El.U in 1 mg aluminium hydroxide (to group E, n = 43). The geometric mean anti-HAV concentration (GMC) measured in mIV/ml by an ELISA method one month after each injection were: group A, 223, 480, 1635; group B, 123, 221, 649; group C, 185, 365, 1085; group D, 144, 323, 1076; group E, 229, 646, 2521. At month 6, the GMC had fallen by approximately 20%. Seroconversion as measured by ELISA was 100% in groups A and E after one injection, and 100% in all groups after three injections; after two injections, only one subject in group C was still negative. The dose effect with HM175 vaccine was significant. There was a good correlation between ELISA and neutralization (radioimmunofocus inhibition test) titres. One month after the second dose, all subjects in groups A and E had both hepatitis A virus immunoglobulin M (HAV IgM) geometric mean titre, (GMT > 5000) and IgG (GMT > 25,000) as measured by a sensitive terminal dilution ELISA.(ABSTRACT TRUNCATED AT 250 WORDS)

A case of HTLV-1 associated tropical spastic paraparesis is described in a Belgian nun who had been working as a midwife in Central Africa. Occupational exposure was the only risk factor identified. Among 2,482 Belgian expatriates in tropical countries, 92% of whom had resided in sub-Saharan Africa for an average of 15.5 years, only one Belgian-born man was found seropositive for HTLV-1. He was married to an African woman and living in Central Africa for 23 years. The risk of HTLV-1 infection is low in Belgian expatriates and on its own does not support generalised anti-HTLV screening in autochthonous Belgian blood donors.

Several diagnostic hepatitis C assays have been developed for the detection of antibodies to different antigens of the virus. This virus is the major cause of non-A, non-B hepatitis. Seventy-nine patients undergoing chronic hemodialysis and/or hemofiltration were tested for the presence of anti-HCV antibodies (anti-C-100-3 antibodies and anti-core antibodies), anti-hepatitis B core antibodies (anti-HBc), and aminotransferases (ALT). Seven patients were positive by one or more of the anti-HCV enzyme linked immunoassays (EIAs), while HCV-RNA was detectable in only four patients. These four patients had at least one, but not necessarily the same, positive anti-HCV EIA. HCV-RNA was not detected in patients who had no antibodies as determined by all six anti-HCV EIAs. All patients with a marker for HCV infection had persistent normal levels of transaminases. Three patients had elevated ALT values without a marker for HCV infection and suffered from hepatitis B virus infection. Anti-HBc was detected in 27/72 patients without any marker and in four patients with a marker of HCV infection. However, HCV-RNA was detectable in only one of these four anti-HBc positive patients. It is concluded that surrogate markers (anti-HBc and serum transaminases) are not useful for identification of HCV carriers in chronic hemodialysis patients.

Seventeen fresh clinical isolates of human cytomegalovirus (HCMV) were examined for their in vitro susceptibility to different potential anti-HCMV drugs, including a series of acyclic nucleoside phosphonate analogues as well as the reference compounds ganciclovir, foscarnet and acyclovir. Three sulfated polysaccharides (heparin, dextran sulfate and pentosan polysulfate) known for their ability to inhibit adsorption of enveloped viruses to the cells were also included in these comparative tests. Of the reference compounds, ganciclovir was the most potent. However, it was about five-fold less potent than the phosphonate derivative (s)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC) and its cyclic form (cHPMPC). All test compounds, including the sulfated polysaccharides, were as active against the clinical isolates as they were against the laboratory strains of HCMV. Furthermore, the choice of the cell line (HEL or MRC-5) did not influence the anti-HCMV activity of the compounds.

In a prospective study on genital infections, the influence of Chlamydial cervicitis on pregnancy outcome was evaluated. In eleven women with Chlamydial cervicitis perinatal outcome was recorded, the placenta was examined and the newborns were screened for Chlamydial conjunctivitis. They were compared with 13 women who were negative for Chlamydia and were delivered immediately after a Chlamydia positive woman. Compared to negative women, women with Chlamydia cervicitis were younger and presented for antenatal care at a later gestational age (difference not significant) and started having sexual intercourse at an earlier age (P less than 0.02). There was a significant association between Chlamydial infection and chorioamnionitis, lower birth weight and severe neonatal infection (P less than 0.05); but a contribution from concomitant genital pathogens could not be completely ruled out. Therefore a screening program for Chlamydia should include screening for other genital infections. While almost all cases of Chlamydia could have been suspected by this technique, a screening based on lactobacillary grades in Pap smears might be helpful for this purpose, even more so because it also facilitates tracing other genital pathogens. Detection of Chlamydial antigen from conjunctival swabs taken immediately after birth did not adequately reflect the risks of neonatal infection in this small group.

In Lisala (Equateur region, Zaire), where a cluster of tropical spastic paraparesis/HTLV-1 associated myelopathy (TSP/HAM) was described, 28/200 (14%) out-patients and hospital personnel were HTLV antibody positive. No differences in prevalences were observed between out-patients and hospital personnel or between ethnic groups. The annual attack rate of TSP/HAM is estimated at 0.15-0.3 per 1000 infected. The ethnic and familial clustering of TSP/HAM together with the high attack rate suggests the presence of co-factors for the progression to disease. This high prevalence of HTLV antibodies contrasts with the low prevalence in another part of the Equateur region.

In Lisala, Equateur province, Zaire, 25 patients from 21 pedigrees were identified with human T-lymphotropic virus type 1 (HTLV-1) associated tropical spastic paraparesis (TSP). In the 10 (48%) pedigrees with additional genuine TSP cases established mainly by history, seven of 10 patients' mothers, no fathers or spouses, one of 59 surviving offspring, five of 105 siblings, and six other close blood relatives had TSP. A child may develop TSP before its mother. Three familial cases were in paternal relatives only. In total, 39 cases (11 men, 28 women) were identified in this population of about 50,000. Half were in the Mundunga minority of less than or equal to 10% (p less than 0.001). The data suggest maternal transmission of HTLV-1 and enhanced TSP susceptibility in those infected due to familial, probably genetic factors.

Human immunodeficiency virus (HIV) infection of MT-4 cells, an HTLV-I-transformed T-cell line, proved to be a rapid and sensitive assay system for the detection of potential antiviral drugs effective against the acquired immune deficiency syndrome (AIDS). Four days after HIV inoculation of the MT-4 cells, viral antigen expression was monitored in parallel with indirect immunofluorescence microscopy and laser flow cytofluorography. When 3'-azido-2',3'-dideoxythymidine (AzddThd, AZT) and 2',3'-dideoxycytidine (ddCyd) were evaluated under these conditions, they inhibited viral antigen expression at a minimum (33% inhibitory) concentration of 0.0004 and 0.02 microM, respectively. Similar minimum effective concentrations were found for AzddThd and ddCyd in assays where inhibition of viral cytopathogenicity was based on cell survival. While laser flow cytofluorography could be best adapted for quantitative measurements, cell survival and reconstitution of disrupted cell aggregates gave an equally rapid and sensitive endpoint; and the latter may be ideally suited for preliminary drug screening.

We present a sero-epidemiological study of 190 Belgian cases of Lyme borreliosis, a multisystemic disease caused by the spirochaete Borrelia burgdorferi and transmitted by a tick bite. The whole spectrum of clinical pictures was observed in these patients, including "erythema chronicum migrans" (63%), neurological involvement (47%) and arthritis (22%), frequently in combination. Our results are compared to findings in other countries. Among the 437 Ixodes ricinus ticks collected in the Sambre and Meuse valleys around Namur, we discovered 43 ticks (9.8%) with spirochaetes in the midgut. The ecology of these arthropods explains why this infection is more prevalent in the spring and the summer. Perhaps for the same reason, the incidence ranges from low near the coast to medium in the central part and high in the wooded south-eastern part of Belgium. The main conclusions are that Lyme borreliosis is endemic in Belgium, that all the clinical pictures can be observed ant that a clear epidemiological case-definition is needed, combining clinical signs and serological results.

In most European countries relapsing fevers, caused by different Borrelia species, are imported diseases. This diagnosis should be considered in a patient with fever recently back from an endemic region, especially if he went through several febrile episodes or if he has jaundice, spleen enlargement, a rash and signs of haemorrhage or meningoencephalitis.

Healthy young adult volunteers, 778 in number, without HBV markers were randomly distributed into groups and administered different lots of a yeast-derived hepatitis B vaccine (YDV) at different dose levels or a commercial plasma-derived vaccine (PDV), according to a 0, 1, 2, 12-month vaccination schedule. The YDV proved to be safe and well tolerated, even when partly purified lots were given. Reactions were mild and transient, comparable to those observed after PDV. One month after three YDV doses, 0-7% of subjects overall had failed to seroconvert; all those evaluated one month after the booster dose had seroconverted. No significant difference was found between the two vaccine types as far as seroconversion rates were concerned. Geometric mean anti-HBs levels following three vaccine doses were higher in seroconverters of the PDV groups. However, a booster dose of YDV resulted in high anti-HBs levels in all groups varying from 11,474 to 51,404 IU l-1 (purified YDV lot), 4915 to 18,832 IU l-1 (partly purified YDV lots) and 11,008 to 15,805 IU l-1 (PDV lots). Of seroconverters to the purified lots of YDV 93% attained 1000 IU l-1 after the booster dose, thus ensuring protection for a number of years. Dose-response studies provided a basis for the selection of 20 micrograms of highly purified YDV as the standard dose.