Defective humoral responses and extensive intravascular apoptosis are associated with fatal outcome in Ebola virus-infected patients.

Ebola virus is very pathogenic in humans. It induces an acute hemorrhagic fever that leads to death in about 70% of patients. We compared the immune responses of patients who died from Ebola virus disease with those who survived during two large outbreaks in 1996 in Gabon. In survivors, early and increasing levels of IgG, directed mainly against the nucleoprotein and the 40-kDa viral protein, were followed by clearance of circulating viral antigen and activation of cytotoxic T cells, which was indicated by the upregulation of FasL, perforin, CD28 and gamma interferon mRNA in peripheral blood mononuclear cells. In contrast, fatal infection was characterized by impaired humoral responses, with absent specific IgG and barely detectable IgM. Early activation of T cells, indicated by mRNA patterns in peripheral blood mononuclear cells and considerable release of gamma interferon in plasma, was followed in the days preceding death by the disappearance of T cell-related mRNA (including CD3 and CD8). DNA fragmentation in blood leukocytes and release of 41/7 nuclear matrix protein in plasma indicated that massive intravascular apoptosis proceeded relentlessly during the last 5 days of life. Thus, events very early in Ebola virus infection determine the control of viral replication and recovery or catastrophic illness and death.

[Filovirus]. / Les filovirus.

Since forty years Marburg and Ebola viruses emerge frequently in Africa and are responsible of viral hemorragic fever outbreaks with high mortality rate. Despite intensive research programs, these viruses remain mysterious: the reservoir is not clearly defined, and the mechanisms leading to their high pathogenicity are poorly understood; a defective or inadapted immune response seems to be the main factor. No specific treatment nor vaccine are available for humans. But encouraging results have been obtained in the treatment of filovirus infections in non human primate model with different products, as recombinant nematode anticoagulant protein, anti sens phosphorodiamidate morpholino oligomers or small interfering RNA.As vaccines, recombinantVSV expressing the GP of filovirus or adenovirus expressing the GP and NP of filovirus are very promising in macaque models.

Antibodies to human immunodeficiency virus in the breast milk of healthy, seropositive women.

Reports of rare cases of suspected transmission of the human immunodeficiency virus (HIV) from mother to children by breast milk have been recently published. To study the factors that possibly limit HIV transmission through breast-feeding, milk samples obtained from 15 healthy, seropositive mothers and 4 seronegative control subjects were studied for the presence of anti-HIV antibodies. All samples from seropositive women contained IgG antibody against envelope glycoproteins gp160 and/or gp120, and 11 of 15 samples contained IgA antibodies against gp160. IgA antibodies against other viral antigens were more rarely recovered, except against the internal proteins of the virus, p18 and p25. The finding of IgA antibodies to HIV-1 in breast milk establishes that the virus elicits a local immune response in heterosexual, seropositive women. The role of local antibodies in the postnatal transmission of HIV remains to be determined.

Phylogenetic analysis of SIV and STLV type I in mandrills (Mandrillus sphinx): indications that intracolony transmissions are predominantly the result of male-to-male aggressive contacts.

Natural SIVmnd and STLVmnd infections of mandrills in a colony at the Centre International de Recherches Médicales de Franceville (CIRMF) in Gabon were investigated by genetic analysis to determine the extent of intracolony transmission. SIVmnd pol sequence analysis indicates that the six strains present in the colony belong to the SIVmnd lentivirus subgroup previously defined according to the only available prototype sequence (SIVmndGB1), which originated from the same colony. The intraanimal nucleotide diversity (1.1-3.1%) was similar in range to that reported in individuals infected by other HIV/SIVs. The interanimal diversity (0.5-4.3%) was not significantly different from that observed in each individual mandrill, indicating an epidemiological link among the SIVmnd isolates of distinct animals within the colony. Phylogenetic analysis of these isolates, together with seroepidemiological and behavior surveillance within the colony, indicates a predominant male-to-male transmission of SIVmnd that probably occurred during bouts of interanimal aggression. Moreover, our results suggest one case of vertical transmission of SIVmnd from a naturally infected founder female to one of her six offspring. The first genetic analysis of STLV isolates from mandrills is also reported here. Partial tax/rex sequences were used to evaluate the diversity between seven STLVmnd isolates and their phylogenetic relationships with other known strains of human and nonhuman primate T cell leukemia virus, types I and II (PTLV-I/II). They all belong to the PTLV-I subtype, but two genetically distinct STLVmnd groups were evidenced within the mandrill colony. The phylogenetic analyses of the STLVmnd isolates, together with seroepidemiological and behavior surveillance of the mandrills, indicate that intracolony transmissions of STLVmnd are also predominantly the result of male-to-male aggressive contacts.

Immunogenicity of variable regions of the surface envelope glycoprotein of HTLV type I and identification of new major epitopes in the 239-261 region.

The reactivity of sera of 96 individuals infected with human T-cell leukemia virus type I (HTLV-I) was tested against various synthetic peptides corresponding to the gp46 immunodominant antigenic domains: residues 86-107, 175-199, and 239-261. The frequency of reactive sera was higher for 175-199 (93%) than for 239-261 (78%) or 86-107 (24%) with some variations in geographical regions and in diseases. The region 239-261 was extensively analyzed and five (linear or conformational) epitopes were found. The reactivity of sera toward functional or immunodominant domains may depend on the sequence of the infecting virus, and the role of three frequent substitutions (asparagine by tyrosine, proline by serine, and serine by proline or leucine at positions 93, 192, and 250 respectively) was established. Finally, the role of the genetic background of the host may condition the humoral immune response as individuals infected by HTLV-Is harboring the same predicted gp46 peptide sequence may recognize one, several, or all regions examined.

Immune response to Treponema pertenue and Treponema pallidum Nichols in patients with yaws.

Human sera from African patients with acute yaws were analysed by Western blot (WB) against antigens of Treponema pallidum Nichols and two Treponema pertenue isolates. The Western blot patterns were remarkably similar from one patient to another, and strains of both subspecies exhibited exactly the same banding pattern. Sera from yaws patients failed to detect at least one antigen in T. pertenue which was absent from T. pallidum.

Biotype and Lior serogroup distribution of enteric Campylobacter isolated from children in Bangui (Central African Republic), and comparison with Penner serotypes.

The new extended biotyping scheme of Lior as well as the slide agglutination technique were applied to 209 strains of enteric Campylobacter isolated from children in Bangui (Central African Republic). Three biotypes of C. jejuni and 2 biotypes of C. coli were identified among the strains; 31.1% were C. jejuni I, 11% C. jejuni II, 2.4% C. jejuni III, 44% C. coli I and 11.5% C. coli II. We were able to serotype 71.3% of the strains with 20 immune sera prepared against strains of Campylobacter isolated previously; 63% of the strains were distributed among the ten most common serogroups. No significant difference was observed in the distribution of biotypes or serogroups between strains from healthy and diarrhoeic children. Comparison of Lior serogroups with Penner serotypes showed that different Penner serotypes may correspond to a Lior serogroup and vice versa.

Antibodies to Campylobacter flagellin recognize epitopes common to phase 1 and phase 2 flagella.

We used a simple method to obtain purified flagellin from Campylobacter, suitable for an immunization procedure in mice. Western blot analysis of cross-reacting antibodies showed that there were epitopes common to phase 1 and 2 flagellins. Analysis by ELISA suggested that certain common flagellar epitopes are conformational, and antibody immobilization tests confirmed that common surface-exposed epitopes exist in a region of flagella necessary for conferring motility to the bacteria.

High levels of anti-Campylobacter-flagellin IgA antibodies in breast milk.

Several studies have shown the beneficial role of immunity against enteric Campylobacter sp. Circulating antibodies against flagellin and possibly maternal antibodies seem to protect against intestinal colonization by Campylobacter. Milk from women in Central Africa (n = 120) and in France (n = 31) were investigated for the presence of anti-flagellin antibodies. Results showed that most French and all African milk possessed anti-flagellin IgA but not IgG. The titres of anti-flagellin IgA were elevated in colostrum and decreased in later milk. Specific activities were constant during lactation, suggesting constant antigenic stimulation. The fact that IgA but not IgG are elicited against flagellin could be due to an infection limited to the mucosal surface.

Species-specific sequence in the repeat 3 region of the gene encoding a putative Loa loa allergen: a diagnostic tool for occult loiasis.

A polymerase chain reaction (PCR)-based method to detect Loa loa DNA in the blood lysate of infected individuals is described. A set of primers was designed to amplify the repeat 3 sequence (15r3) of the gene encoding a putative L. loa allergen. The qualitative PCR was carried out using blood lysates from subjects from an L. loaendemic area of Gabon where loiasis exists sympatrically with Mansonella perstans, and from individuals from a loiasis-free area in Togo infected concomitantly with M. perstans and Onchocerca volvulus. No specific amplification was observed after ethidium bromide staining of a gel containing M. perstans and O. volvulus control samples. In contrast, a 396-basepair (bp) DNA was detected in all L. loa microfilaremic individuals and in seven of the 20 L. loa amicrofilaremic subjects diagnosed by leukoconcentration. Qualitative Southern blots carried out at high stringency (65 degrees C) using 15r3 oligonucleotide probe revealed hybridization only with L. loa samples (5 of 5 microfilaremic individuals and 15 of 20 amicrofilaremic individuals), confirming the results obtained with ethidium bromide staining of PCR products. We conclude that this 396-bp sequence could be used as a species-specific diagnostic tool for occult loiasis in an endemic area with concurrent filarial infections.

Lack of malaria parasite transmission between apes and humans in Gabon.

The International Center for Medical Research (CIRMF) is located in an area highly endemic for malaria in southeastern Gabon, where humans and apes (gorillas and chimpanzees) are living in the same geographic area. The presence of the CIRMF primate center housing apes (59 chimpanzees and nine gorillas in 1994) within the city of Franceville provided an opportunity to investigate the capability of cross-transmission of malaria species from humans to apes. The main vector of human malaria, Anopheles gambiae, was found in the primate center and in a nearby populated area of Franceville. Despite high malaria transmission in humans of both Plasmodium falciparum and P. malariae (mean of 43% cumulative prevalence in schoolchildren), none of the apes were found infected with plasmodia during a six-month investigation. However, low antibody levels against sporozoite and blood stages of both P. falciparum and P. malariae were detected in a few chimpanzees and gorillas. These results demonstrate that only rarely would apes be bitten in the field by mosquitoes infected with human malaria parasites. In the case of infection proven by serology, we did not find any evidence that blood-stage malaria parasites were able to the gametocyte stage. The absence of any established malaria transmission cycle within the primate colony of CIRMF indicates that apes cannot be considered as animal reservoirs for human malaria parasites in this environment.

Diarrheal morbidity and mortality in children in the Central African Republic.

Diarrheal morbidity and mortality in children less than 5 years old were studied in Bangui, Central African Republic, by a cluster survey. We found a high prevalence of diarrheal disease with an estimated annual incidence of 7 episodes of diarrhea per child per year. The estimated annual mortality rate for children less than 5 years old was 28.6 per 1,000 and 85.8 per 1,000 for infants; 51.6% of deaths were reported to be associated with diarrhea. During the survey, stool specimens were collected from 133 children with current diarrhea and 117 control children to study the etiologic agents of diarrheal disease in the community. An enteric pathogen was identified in 58% of diarrheal children's stools and 48% of stools of well children. A statistically significant association between diarrhea and rotavirus was found, with it being isolated from 8 of 33 (24%) of stools of infants with diarrhea compared to 0 of 25 (0%) of control infants. Isolation rates for Campylobacter jejuni, Entamoeba histolytica, pathogenic Escherichia coli, and other bacterial enteropathogens did not differ significantly between children with diarrhea and control children.

PIP: Using a cluster sample survey, researchers studied diarrheal morbidity and mortality in children 5 years old in Bangui, Central African Republic in November 1983. They collected fecal samples from all children who had diarrhea the day of the investigation. They also took stools from children not ill with diarrhea at the time and who had 3 stools/day for the past week. Researchers looked for an age matched control in the same cluster, but not in the same home, for each child with diarrhea. They were unable to explain at least 42% of the diarrhea cases and much more when they considered the high isolation rates among the nondiarrheic children. This highlights the need for further research to better understand the carrier state. 57.8% of the diarrheic children's stools had 1 or more enteric pathogens, while 47.8% of the nondiarrheic children's tools did. In children 1 year old, rotavirus was the most frequent enteropathogen associated with diarrhea (p.05). Parasitic organisms were found more frequently as the age of the child increased. A high carrier state of different enteric pathogens existed, including Campylobacter jejuni, Entamoeba histolytica, Giardia intestinalis, and enteropathogenic Escherichia coli. The annual child and infant mortality rates were very high (28.6/1000 and 85.8/1000 respectively). Death was related to diarrhea in 19.1% of the cases and associated with diarrhea in 50% of the cases. The annual attack rate stood at 7 episodes/child which is greater than is usually reported.

Lympho-cutaneous Kaposi's sarcoma in an African pediatric AIDS case.

A case of disseminated Kaposi's sarcoma with lymphoid and mucocutaneous involvement in an African infant with acquired immune deficiency syndrome is reported. The child died within 2 months after recognition.

PIP: Co-infection with acquired immunodeficiency syndrome (AIDS) and Kaposi's sarcoma is not uncommon in Europe, but is rare in Africa and not previously reported in infants. This article documents the case of an 11-month-old African boy with lymphocutaneous Kaposi's sarcoma. The infant was brought to a hospital in the Central African Republic with chronic diarrhea and disseminated lymphadenopathy. Also present were fever, cough, weight loss, a gingivostomatitis with herpes-like vesicles, hepatomegaly, splenomegaly, and cervico-axillo-inguinal lymphadenopathy. The adenopathies 1st occurred when the infant was 7 months of age and were followed 1 month later by the emergence of 12 dark brown or black velvet raised cutaneous nodules. The diagnosis of Kaposi's sarcoma was confirmed by lymph node and skin nodule biopsies. Also indicative of Kaposi's sarcoma was the presence of abortive vascular foci at a distance from the skin's surface and the cell proliferation. Both the infant and his asymptomatic mother were seropositive for antibodies to human immunodeficiency virus (HIV)-1. The skin lesions in this case presented the special infiltrative characteristic of AIDS-related Kaposi's sarcoma. The infant died 2 months after presentation at the hospital. By the last weeks of his life, the cutaneous nodules had covered the entire body. Death was from pleuropneumopathy. Given the high prevalence of HIV-1 infection in the Central African Republic, more such cases can be expected.

An outbreak of human Semliki Forest virus infections in Central African Republic.

Semliki Forest (SF) virus was responsible for an outbreak of febrile illnesses in Bangui, Central African Republic (CAR), during October-December 1987. The virus was isolated at first from mosquitoes, mainly Aedes africanus, collected August-October in a gallery forest 100 km from Bangui. During October-December, 22 isolations of SF virus were made from serum samples collected from patients in Bangui presenting with fever, severe persistent headache, myalgia, arthralgia, and a convalescence marked by asthenia. During the same period, 8 SF virus isolates were obtained from mosquitoes collected in Bangui, mainly from Ae. aegypti. Europeans, particularly soldiers who had recently arrived from France, were affected. Antibodies to alphaviruses had been previously detected in a high proportion of resident human populations in CAR. We conclude that SF virus is a human pathogen.

Human occult loiasis: improvement in diagnostic sensitivity by the use of a nested polymerase chain reaction.

The development of control strategies for loiasis is of crucial importance in endemic areas and depends heavily on the accurate identification of occult-infected individuals. A polymerase chain reaction (PCR) and nested polymerase chain reaction (nested PCR) were developed and based on sequences of the repeat 3 region (15r3) of the gene encoding a Loa loa 15-kD protein. The assays was performed on 20 blood samples from occult-infected subjects and 30 from field-collected amicrofilaremic individuals. The size of the initial PCR product was 396 basepairs (bp). When this initial amplification using primers 15r3(1) and 15r3(2) was carried out for 30 cycles, the PCR products from three of the 20 occult-infected and five of the 30 amicrofilaremic individuals were visualized after electrophoresis by staining the gel with ethidium bromide. Subsequent Southern blotting and hybridization with the specific probe revealed hybridization in 19 of 20 occult-infected and 23 of 30 amicrofilaremic samples but only after two days of exposure of the blot to the x-ray film. When the nested PCR was carried out (product size = 366 bp, primers 15r3(3) and 15r3(4)), 19 of 20 occult-infected and 23 of 30 amicrofilaremic samples that were positive by Southern hybridization of the initial PCR products were strongly positive by staining with ethidium bromide. Qualitative Southern blotting of the nested PCR products using the same probe previously described confirmed the ethidium bromide staining results after a very short exposure time of 4 hr. These results demonstrate that the nested PCR amplification product is specific and that its sensitivity in detecting occult loiasis is 95%. This approach has significant promise for the screening of large human populations for active loiasis without the requirement for blotting and hybridization of the PCR products.

Postischemic function and protein kinase C signal transduction.

BACKGROUND: The protective effects of myocardial preconditioning may occur by way of multiple mechanisms, with G-protein-mediated protein kinase C (PKC) translocation as a final common pathway. In this study we investigate the pharmacologic induction of preconditioning, by PKC translocation, using PKC agonists/antagonists to reveal its effects on contractile function after myocardial ischemia. METHODS: Langendorff-perfused rabbit hearts received: (1) control; (2) dimethyl sulfoxide (vehicle); (3) acetylcholine (0.55 mmol/L; PKC agonist); (4) 1,2-s,n-dioctanoylglycerol (DOG; 22 mmol/L; PKC agonist); (5) chelerythrine (0.8 mmol/L; PKC antagonist); or (6) DOG-chelerythrine followed by a 2-hour ischemic period, using modified St. Thomas cardioplegia and a 45-minute reperfusion period. The period of ischemia was chosen so as to allow for improvement by appropriate agonists. To observe metabolic changes, tissue nucleotides and nucleosides were measured. Membrane and cytosolic fractions of PKC were determined by an anti-PKC antibody directed against the PKC delta isozyme. Lactate levels and myocardial pH were measured. RESULTS: The PKC agonists DOG and acetylcholine showed the greatest recovery of developed pressure (68% +/- 2%, 60% +/- 9%, respectively). Although pH, lactate, and nucleotide levels were similar between groups at all times, myocyte PKC translocation demonstrated 25% of PKC delta isoforms on cell membrane sites during baseline, which shifted to 67% delta 17% with unprotected ischemia. DOG mimicked this shift with 58% delta 12% of PKC delta isoforms on membranes, which was also blocked by chelerythrine to 35% +/- 7%. CONCLUSIONS: These data demonstrate that PKC translocation results in improved postischemic function, not by alteration of energetics or metabolism, and deserves further investigation.

Delta opioid receptors and low temperature myocardial protection.

BACKGROUND: Cardiac surgery continues to be limited by an inability to achieve complete myocardial protection. This may result from the use of hypothermic cardioplegia. Interestingly, the subcellular changes of animal hibernation parallel the altered biology of induced hypothermic myocardial ischemia, but are well tolerated by hibernated mammalian myocardium. Evidence indicates this protection is mediated by activation of the delta opioid receptor, which elicits profound metabolic effects at the whole animal, organ, and cell level. In this study, we sought to determine if pentazocine, with agonist activity at the delta opioid receptor, could improve myocardial recovery following global ischemia over a wide range of temperatures. METHODS: Isolated rabbit hearts received either standard cardioplegia or were pretreated with racemic, d or 1 isomer pentazocine. Hearts were then subjected to 2 hours at 34 degrees C, or 3.5 hours at 20 degrees C, or 4 hours at 10 degrees C of cardioplegic ischemia and reperfused. Functional recovery was compared to controls. RESULTS: Isovolumic developed pressure, coronary flow, oxygen consumption, and ultrastructural preservation were enhanced with pentazocine delta opioid mediated protection, which appears to be additive to standard cardioplegia, even at low temperatures. CONCLUSIONS: Teleologically, delta opioid protection parallels animal hibernation, which occurs from 34 degrees down to 0 degrees C. The use of delta opioid receptor agonists may have important clinical implications for cardiac surgery and deserves further study.

Peripheral facial paralysis and HIV infection: report of four African cases and review of the literature.

Four cases of infranuclear facial palsy associated with infection by the human immunodeficiency virus in young heterosexual African patients are reported. Two cases were healthy HIV carriers, one patient manifested AIDS-related complex, and one case fulfilled the CDC criteria for AIDS. Two patients had a typical Bell's palsy, one presented with manifest cephalic Herpes zoster infection and one, who suffered from facial diplegia, could be considered to have a cephalic form of Guillain-Barré syndrome. A review of the literature confirmed that peripheral facial palsy can occur at any stage of HIV infection and in various clinical contexts. In stages I and II of the HIV infection, patients may develop either Bell's palsy or Guillain-Barré syndrome. In stages III and IV, when the cellular immunity has begun to decline, Herpes zoster-related facial paralysis, seventh cranial nerve involvement secondary to meningeal lymphomatosis, and peripheral facial paralysis as one aspect of widespread chronic peripheral neuropathy may also occur.

Antibodies to haemorrhagic fever viruses in Madagascar populations.

Sera of 381 adult people from 5 areas in Madagascar were tested by the indirect immunofluorescence method for antibodies against Congo-Crimean haemorrhagic fever and Rift Valley fever viruses (Bunyaviridae), Ebola (strains Zaire and Sudan) and Marburg viruses (Filoviridae), and Lassa virus (Arenaviridae). The highest prevalence rate was that of Ebola virus (4.5%). As no haemorrhagic syndrome has been found associated with this virus, the possible presence of a less pathogenic, antigenically related, strain is discussed. The prevalences of Congo-Crimean haemorrhagic fever and Rift Valley viruses were very low, despite previous viral isolations from potential vectors. No serum reacted against Lassa or Marburg antigens. The results are analysed in the light of the geographical and bioecological characteristics of Madagascar, which is a true 'microcontinent' very different from the African mainland.

Low prevalence of neuro-psychiatric clinical manifestations in central African patients with acquired immune deficiency syndrome.

In order to evaluate the frequency of neurological and psychiatric disorders in central African patients with acquired immune deficiency syndrome (AIDS), 93 inpatients at the National Hospital Centre of Bangui were selected according to the World Health Organization (Bangui) clinical definition of AIDS and were confirmed to be serologically positive for human immunodeficiency virus (HIV) 1 (92/93) or HIV 2 (1/93) by Western blot. Neurological (11/15) and psychiatric (4/15) abnormalities were clinically detected in 16% (15/93) of African patients with AIDS. In this series, the prevalence of neuro-psychiatric disorders appeared to be lower than in Europe and North America.