Diagnostic accuracy and acceptability of molecular diagnosis of COVID-19 on saliva samples relative to nasopharyngeal swabs in tropical hospital and extra-hospital contexts: The COVISAL study

A prospective study was conducted among different intra and extra-hospital populations of French Guiana to evaluate the performance of saliva testing compared to nasopharyngeal swabs. Persons aged 3 years and older with mild symptoms suggestive of COVID-19 and asymptomatic persons with a testing indication were prospectively enrolled. Nasopharyngeal and salivary samples were stored at 4°C before analysis. Both samples were analyzed with the same Real-time PCR amplification of E gene, N gene, and RdRp gene. Between July 22th and October 28th, 1159 persons were included, of which 1028 were analyzed. When only considering as positives those with 2 target genes with Ct values <35, the sensitivity of RT-PCR on saliva samples was 100% relative to nasopharyngeal samples. Specificity positive and negative predictive values were above 90%. Across a variety of cultures and socioeconomic conditions, saliva tests were generally much preferred to nasopharyngeal tests and persons seemed largely confident that they could self-sample. For positive patients defined as those with the amplification of 2 specific target genes with Ct values below 35, the sensitivity and specificity of RT-PCR on saliva samples was similar to nasopharyngeal samples despite the broad range of challenging circumstances in a tropical environment.

Covid-19 à Mayotte : profil épidémiologique d’une année de crise

Introduction

Le 13/03/20, Mayotte déclare son premier cas de Covid-19. Le contexte socio-économique précaire rend inconcevable l’application des recommandations de prévention. Bien que la moitié de la population ait moins de 18 ans ; chez les adultes, la prévalence des facteurs de risque de formes graves fait redouter une saturation de l’unique hôpital de l’île : 38 % d’HTA, 12 % de diabète tandis que l’IMC moyen est de 26,9 kg/m².

Matériels et méthodes

Afin de comprendre la dynamique et la sévérité du Covid-19 à Mayotte, plusieurs dispositifs de surveillance ont été mis en place. Ce travail décrit l’évolution épidémique du 9/03/20 au 14/03/21 en distinguant deux vagues différentes du fait de l’émergence de variants: 2020 (9/03/20-31/12/20) versus 2021 (01/01/21-14/03/21).

Résultats

L’épidémie a débuté en mars 2020 avec un pic en mai (taux d’incidence (TI) de 133/100000 hbts). L’âge médian des cas était de 36 ans et la plupart d’entre eux était sans activité professionnelle. Le TI a diminué pour passer début juillet, sous le seuil d’alerte, suggérant une accalmie durant l’hiver austral. Cette première vague s’est avérée relativement peu sévère avec un maximum de cas hospitalisés en S21 : 51 patients hospitalisés dont 11 en réanimation. La circulation virale a continué sans impact sanitaire majeur jusqu’en décembre 2020 où l’Afrique du Sud a signalé l’émergence du variant 501Y.V2. Quelques semaines après les Comores, Mayotte enregistrait une dégradation rapide et intense de la situation: doublement du TI, triplement du taux de positivité Sars-Cov-2 (TP) entre mi-décembre et mi-janvier, y compris chez les 0-14 ans. En S6-2021, le TI a atteint un pic (894/100000 hbts) tout comme le TP culminant à 28 %. Deux enquêtes flash en février ont montré la part majoritaire d’un variant avec la mutation 501Y, représentant 87 % (150/172) des échantillons analysés par criblage. Les indicateurs hospitaliers témoignaient de la sévérité de cette nouvelle vague avec un pic atteint en S18-2021 : 148 patients hospitalisés dont 27 en réanimation, majoritairement des formes oxygéno-requérentes. En 2021, 149 cas ont été admis en réanimation contre 104 en 2020 (sex ratio H/F = 1,9). Parmi les patients présentant une forme pulmonaire, le profil des cas admis en réanimation en 2021 a changé par rapport à 2020 : ils étaient significativement plus jeunes (57 vs 62 ans) et présentaient un profil de comorbidités différent. Au total, en un an, 18899 cas ont été confirmés biologiquement et 253 patients admis en réanimation: ils correspondaient à 203 cas de formes pulmonaires, 46 cas de portage asymptomatique et 14 cas de syndrome inflammatoire multi-systématique associé à une infection par le Sars-Cov-2. En 2021, 88 patients sont décédés contre 55 en 2020; âges médians respectifs de 73 et 64 ans.

Conclusion

Le confinement de février 2021 s’est suivi d’une inversion de la tendance épidémique. Fin mars, l’épidémie se poursuit avec un TI de 63/100000 hbts. Alors que moins de 5000 personnes ont été vaccinées à deux doses, la vigilance est de mise pour ce territoire vulnérable.

Fungemia in the French department of Mayotte, Indian Ocean: A 10 years survey

OBJECTIVE

This study aimed at providing original data on fungemia in the Centre Hospitalier de Mayotte in terms of prevalence, epidemiological characteristics of infected patients, yeast species distribution and profile of in vitro antifungals susceptibility.

METHODS

A total of 223 positive blood cultures for yeasts were retrospectively reported during the period April 2010-April 2020.

RESULTS

Ninety-five episodes were identified corresponding to an incidence rate of 3.7 cases/100,000 inhabitants. The average age of patients was 33.5 years, and 63.3% patients were hospitalized in intensive care unit. The main co-morbidities were surgery in the 30 days prior to fungemia (27.8%), neoplasia (22.8%), parenteral nutrition (17.7%), diabetes (16.5%) and immunosuppressive medications (31.6%). Candida spp accounted for the majority of isolates (92.4%) with a predominance of non-albicans species (55.8% vs 33.7%), including C. albicans (33.7%), C. tropicalis (30.5%) and C. parapsilosis (20%). The antifungal susceptibility profiles did not differ from expected results for each species and did not change significantly over time.

DISCUSSION

Fungemia remain frequent hospital infections associated with high mortality in Mayotte. The vast majority of fungemia was due to Candida spp. Non-albicansCandida species reach half of the Candida isolates with a high percentage of C. tropicalis. Surprisingly, no case of candidemia due to C. glabrata were identified. The management of candidemia remains satisfactory and the treatment was adapted according to the international recommendations. However, the high susceptibility of Candida spp. isolates to fluconazole may invite to reconsider the use of this molecule as empirical and first-line treatment of candidemia in Mayotte.

Biological monitoring of workers exposed to engineered nanomaterials

As the number of nanomaterial workers increase there is need to consider whether biomonitoring of exposure should be used as a routine risk management tool. Currently, no biomonitoring of nanomaterials is mandated by authoritative or regulatory agencies. However, there is a growing knowledge base to support such biomonitoring, but further research is needed as are investigations of priorities for biomonitoring. That research should be focused on validation of biomarkers of exposure and effect. Some biomarkers of effect are generally nonspecific. These biomarkers need further interpretation before they should be used. Overall biomonitoring of nanomaterial workers may be important to supplement risk assessment and risk management efforts.

A postpartum haemorrhage package with condom uterine balloon tamponade: a prospective multi-centre case series in Kenya, Sierra Leone, Senegal, and Nepal

OBJECTIVE

To evaluate the effectiveness and safety of an ultra-low-cost uterine balloon tamponade package (ESM-UBT™) for facility-based management of uncontrolled postpartum haemorrhage (PPH) in Kenya, Sierra Leone, Senegal, and Nepal.

DESIGN

Prospective multi-centre case series.

SETTING

Facilities in resource-scarce areas of Kenya, Sierra Leone, Nepal, and Senegal.

POPULATION

Women with uncontrolled postpartum haemorrhage in 307 facilities across the four countries.

METHODS

A standardised ESM-UBT package was implemented in 307 facilities over 29 months (1 September 2012 to 1 February 2015). Data were collected via a multi-pronged approach including data card completion, chart reviews, and provider interviews. Beginning in August 2014, women who had previously undergone UBT placement were sought and queried regarding potential complications associated with UBT use.

MAIN OUTCOME MEASURES

All-cause survival, survival from PPH, and post-UBT use complications (surgery, hospitalisation, antibiotics for pelvic infection) associated with UBT use.

RESULTS

201 UBTs were placed for uncontrolled vaginal haemorrhage refractory to all other interventions. In all, 38% (71/188) of women were either unconscious or confused at the time of UBT insertion. All-cause survival was 95% (190/201). However, 98% (160/163) of women survived uncontrolled PPH if delivery occurred at an ESM-UBT online facility. One (1/151) potential UBT-associated complication (postpartum endometritis) was identified and two improvised UBTs were placed in women with a ruptured uterus.

CONCLUSIONS

These pilot data suggest that the ESM-UBT package is a clinically promising and safe method to arrest uncontrolled postpartum haemorrhage and save women's lives. The UBT was successfully placed by all levels of facility-based providers. Future studies are needed to further evaluate the effectiveness of ESM-UBT in low-resource settings.

TWEETABLE ABSTRACT

Evidence for ESM-UBT as a clinically promising and safe method to arrest uncontrolled PPH and save women's lives.

Social Network and Health Researchers and Professionals Mobility in Africa: Lessons Learned from AFRICA BUILD Project

OBJECTIVE

Promote mobility between South-South and South-North for improving level of researchers, staff and students through a platform.

METHODS

The methodology is based a filling of a questionnaire about offer or demand. Material is composed a computer connected Internet.

RESULT

we registered about 203 demands and 31 offers from partners.43 mobilities were executed completely.

CONCLUSION

The results indicate a real need of mobility for researchers and health professionals in Africa. The important number of mobility demands made by external researchers and professionals (from outside the AFRICA BUILD Consortium) may be constrained by the difficulty to find adequate funding.

[Influenza sentinel surveillance network improvement in Senegal and results]

Influenza surveillance in Senegal was initially restricted to the identification of circulating strains. The network has recently been enhanced (i) to include epidemiological data from Dakar and other regions and (ii) to extend virological surveillance to other respiratory viruses. Epidemiological data from the sentinel sites is transmitted daily by mobile phone. The data include those for other febrile syndromes similar to influenza-like illnesses (ILI), corresponding to integrated approach. Also, clinical samples are randomly selected and analyzed for influenza and other respiratory viruses. There were 180,192 declared visits to the 11 sentinel sites between week 11-2012 and week 52-2013; 24% of the visits were for fever syndromes and 25% of the cases of fever syndrome were ILI. Rhinoviruses were the most frequent cause of ILI (19%), before adenoviruses (18%), enteroviruses (18%) and influenza A viruses (13%). Co-circulation and co-infection were frequent and were responsible for ILI peaks. In conclusion, it is clear that the greatest advantage of this system is the ease with which it can be implemented, thanks to the availability of mobile phones and mobile phone networks. We recommend this solution for other African countries, because it performs very well and provides rapid benefits in terms of public health decision-making.

Evaluation of the antineoplastic activity of mitoxantrone–l-carnitine combination therapy on an experimental solid form of ehrlich tumour in mice

We have commenced a series of experiments to evaluate the effect of carnitine derivatives on the antineoplastic activity of mitoxantrone (MX) on various animal cancers. This report describes the therapeutic effect of MX in combination with l-carnitine (LCAR) on the growth of a solid form of Ehrlich tumour inoculated into mice. LCAR was administered subcutaneously at doses of either 200 or 100mgkg(-1) on day 6 and 13 after tumour inoculation, 1h prior to the treatment with MX. Mitoxantrone was administered intravenously at doses of 3 or 6mgkg(-1). We found that LCAR had no potentiating effect on the efficacy of MX, in terms of either slowing tumour growth or increasing the survival of mice. Nevertheless, therapeutic effects can be assumed at higher doses of both drugs based on values calculated from an index of relative hazards.

Differences in circulating dendritic cell subtypes in peripheral, placental and cord blood in African pregnant women

Dendritic cells (DC) are important for induction of primary immune responses and immunological tolerance. Changes in the frequency of DC subsets were analyzed in peripheral blood from pregnant women (mPB) and compared to placental blood (PB) and cord blood (CB). DCs were identified by flow cytometry in whole blood as lineage negative and HLA-DR-positive cells. Different DC subtypes were identified with CD123 and CD11c markers. In these data, the percentage of DC was significantly lower in mPB, PB and CB than in control women, but the absolute number of DC was higher in CB, suggesting that numbers of DC in CB do not explain the decrease of the immune response in newborn infants. Myeloid DCs (MDC) decreased in all compartments of pregnant women compared to control women, especially in mPB where MDC became lower than lymphoid DCs. An increase of less differentiated DC was observed in mPB and CB from pregnant women. DCs in pregnant women were mainly immature DC with a proportion of CD83-positive DC, identical as control women. The levels of IFNgamma, TNFalpha, IL-2, IL-4, IL-5 and IL-10 were not different in the three compartments (mPB, PB, CB). In conclusion, the phenotype and subset of DCs were different in pregnant women than in control women, suggesting a role in maintenance of immune tolerance against the fetus. The distribution of DC subsets was different in mPB, PB and CB. Their role in the regulation of immune response remains to be elicited.

Gamma interferon-producing CD4 T-cells correlate with resistance to Mycoplasma mycoides subsp. mycoides S.C. infection in cattle

Contagious bovine pleuropneumonia (CBPP), caused by Mycoplasma mycoides subsp. mycoides SC (MmmSC), is one of the most significant cattle disease in Africa. The control measures, which led to eradication from numerous countries are not feasible in Africa where the only prophylaxis relies on vaccination. However, the attenuated vaccines, used up to now in Africa, are of low efficiency. The development of an improved vaccine is, therefore, a necessity. The purpose of this study was to compare some immunological parameters in MmmSC-infected cattle (endobronchial versus natural in-contact infection) and assess the response in correlation with the clinical outcome (death versus recovery). Characterization of the immune parameters elicited in recovered animals, known to be refractory to new infection, will be an important step towards development of new vaccines against CBPP. A significant outcome of this study was the demonstration that all MmmSC-infected cattle developed a MmmSC-specific cell-mediated immune response. A kinetic analysis of the MmmSC responsiveness showed that the main difference between endobronchially- and in-contact infected animals was the delay before the onset of the MmmSC-specific immune response. The first MmmSC-responding PBMC sample was selected from each animal for cell phenotyping. The phenotypic analysis of this early MmmSC-induced response revealed the predominant contribution of the CD4 T-cells in all animals whereas IFNgamma was only constantly produced in recovered animals. Evolution of this early MmmSC-specific immune response was then followed by a kinetic analysis of the MmmSC-induced CD4 T-cell response and IFNgamma released. The results demonstrated that in recovered animals, the MmmSC-specific CD4 Th1-like T-cell response was maintained until slaughtering whereas in animals with acute disease, progression of CBPP was associated with a decreased ability of the PBMC to produce IFNgamma. The results led to the identification of immune parameters, which correlate with protection against CBPP and to a relevant strategy for the development of improved vaccines against this disease.

Seasonality in the transmission of schistosomiasis and in populations of its snail intermediate hosts in and around a sugar irrigation scheme at Richard Toll, Senegal

Irrigation for intensive sugar cultivation started in the early 1980s at Richard Toll, some 100 km from the mouth of the Senegal River. Infections with Schistosoma mansoni were first seen in late 1988. This study records quantitative snail surveys for over 3 years from 1992 at sites representing different habitats in and around the irrigation scheme. Populations of both Biomphalaria pfeifferi (the intermediate host of S. mansoni) and Bulinus spp. (mainly B. truncatus, the local host of S. boris) peaked in late 'spring' or early 'summer', depending on the habitat, and then remained low until the following spring', B. pfeifferi favoured smaller, man-made habitats with most transmission between May and August each year. The less abundant Bulinus spp. favoured larger natural and man-made habitats with most S. bovis transmission between April and July. S. mansoni infections were more, but S. bovis infections were less abundant than other trematodes in their respective snail hosts. Ecological changes in the early 1980s due to sugar irrigation pre-dated similar, more widespread changes in the late 1980s when the completion of dams across the Senegal River prevented seasonal rain fed floods and sea water intrusion. S. mansoni has since spread rapidly around Richard Toll. The incompatibility of the local S. haematobium strains with the dominant bulinid snails has so far prevented an epidemic of urinary schistosomiasis at Richard Toll, but the invasion of similar downstream habitats by susceptible B. globosus is worrying. The principal control measure, chemotherapy, given in the 'winter' would minimise the rate of reinfection. It could be reinforced by judicious mollusciciding within the sugar irrigation scheme but not elsewhere.

[Fertility after ectopic pregnancy at the University Hospital in Dakar]

The aims is to evaluate fertility and medical cost about post ectopic pregnancy follow up. It is about a retrospective and descriptive study about 337 patients who have the opportunity to get a salpingectomy for an ectopic pregnancy between 1989 and 1997 at Le Dantec Gynecological and Obstetrical Clinic. After the ectopic pregnancy cure, women are followed with contraception, just time before trying to obtain another pregnancy. The studied parameters are: age, parity, socio-economical status, level of instruction, obstetrical and gynecological antecedents, Chlamydia serology, hysterosaipingography data, fertility after ectopic pregnancy, fees related to the cost of follow up after ectopic pregnancy. Data exploitation is done through an epidemiologic programme named Epi Info version 5 The average age of the patients was 27 years and that of the parity was 2.70. 87.83% of women were married. More than the half of those patients came from the suburb of Dakar. 171 patients (50.74%) were followed regularly, the other 166 (49.26%) disappeared. A Chlamydia trachomatis infection was found among 23.4% of cases. A tubal obstruction was noted in the level of the horns at 12.5 % of women. No case of maternal death was observed. Among 59 patients who wished a pregnancy, 34 ectopic pregnancy had been obtained (57.62%) in 4 month after stopping contraception and 26 cases of a new ectopic pregnancy. The expenses of medical cure after ectopic pregnancy are about 17.814 to 71,574.65 F CFA with an average of 38,689 F CFA (389.89 FF). Medical care after ectopic pregnancy raises a lot of problems: --some patients disappeared probably because of the inaccessibility of financial cost, --the high rate of Chlamydial trachomatis infection, an hypofertility after ectopic pregnancy. To combat this, we have to insist in the prevention of sexually transmitted diseases in general and of the chlamydial infection in particular. We have also to insist in the early diagnosis of the ectopic pregnancy. At last, we must set up a registre of ectopic pregnancy at the national level.

The ISOBM TD-7 Workshop on hCG and related molecules. Towards user-oriented standardization of pregnancy and tumor diagnosis: assignment of epitopes to the three-dimensional structure of diagnostically and commercially relevant monoclonal antibodies directed against human chorionic gonadotropin and derivatives

The ISOBM TD-7 hCG Workshop was established to characterize the molecular epitope structure and specificities of a panel of diagnostically relevant monoclonal antibodies (MAbs) directed against human chorionic gonadotropin (hCG) and its derivatives, and to consider how this information could be used to improve comparability of immunoassay results for these analytes. In this multicenter study, 27 MAbs have been characterized in detail as to their main and fine specificities by direct binding-, competitive- and sandwich-RIA, -ELISA, BIAcore and Western blotting. Antigens used in the study included the upcoming first WHO reference reagents for immunoassay, i.e. nick-free hCG (hCG), nicked hCG (hCGn), hCG alpha-subunit (hCGalpha), hCG beta-subunit (hCGbeta), nicked hCG beta-subunit (hCGbetan), hCG beta-core fragment (hCGbetacf), synthetic peptides of hCGbeta C-terminal peptide (hCGbetaCTP), and homologous hormones, luteinizing hormone (LH) and subunits (LHbeta) from various species. Correct classification of blinded internal controls demonstrated the reliability of the MAb referencing approach. Three-dimensional molecular epitope assignment was possible in many instances by comparing immunoreactivity of the ISOBM MAbs (n = 27) to a large panel of MAbs (n = 18) previously well characterized in the Innsbruck (P.B.) and Paris (J.M.B.) laboratories. All three major antibody specificities (alpha, n = 1; beta, n = 21; alphabeta, n = 5) were represented in the TD-7 MAb panel. HCGbeta MAbs could further be subdivided into (i) those recognizing hCGbeta only (epitopes: beta(6), n = 1; beta(7), n = 2; beta(14), n = 1) and (ii) those recognizing hCGbeta + hCG (beta1, beta2, beta4, beta5, n = 10; beta8 and beta9, n = 9). Members of the latter group were specific either for hCG + hCGbeta + hCGbetacf (beta1, n = 3) or hCG + hCGbeta + hCGbetaCTP (beta8, n = 6; beta9, n = 1) or in addition to hCG + hCGbeta + hCGbetacf recognized hLH/hLHbeta to a minor (beta2, n = 3; beta4, n = 3) or similar degree (beta5, n = 1). Epitopes were (i) located on the first and third loops protruding from the cystine knot of hCGbeta (beta2-beta6, aa hCGbeta20-25 and 68-77), (ii) presumably centered around the knot itself (beta1), or (iii) on hCGbetaCTP (epitope beta8 = hCGbeta141-144, beta9 = hCGbeta113-116). The ISOBM panel of MAbs represents all major epitope specificities suitable for the design of specific sandwich immunoassays. High analyte variability in serum and urine during the course of pregnancy and tumor development favors certain epitope combinations. For routine diagnostic purposes, assays recognizing a broad spectrum of hCG/hCGbeta variants such as hCG + hCGn + hCGbeta + hCGbetan + hCGbetacf + -CTPhCG + -CTPhCGbeta may be useful. Low cross-reactivity against related glycoprotein hormones (e.g. hLH) and their derivatives is mandatory. These criteria are best met by combinations of MAbs directed against epitopes located around the cystine knot (beta1) and against those encompassing the top of loops 1 and 3 on hCGbeta (beta2, beta4). The first WHO reference reagents for immunoassay of hCG and hCG-related molecules being prepared by the IFCC should facilitate characterization of what assays for 'hCG' are measuring. The next step towards improving between-laboratory comparability of measurements of hCG/hCG derivatives in pregnancy and oncology is provided by results of this TD-7 Workshop.

Effect of acetyl-L-carnitine on leukemia L1210 resistant to mitoxantrone

Supportive care in tumour chemotherapy is a subject of intensive research. The complications of cytostatic therapy are a cause of extensive research of their pharmacological interactions and side effects. The immunologic and biochemical changes accompanying tumours are the factor that is most responsible for the worsening of the physiology of the host. Regimens containing carnitine and it's acetyl-derivative are used in many cases, among others even for preventing hepatotoxicity. Our hypothesis was to verify the supporting metabolic effects of acetyl-L-carnitine hydrochloride (ALC) in combined therapy with mitoxantrone (MX) and hepatotoxic cytostatic drugs including alkylating agents. This present report describes the effect of ALC in combination with MX on DBA/2 male mice bearing a transplantable L1210 leukemia resistant to MX. The criterion for evaluation of effect was the length of survival time of experimental animals. The proportional-hazards model quadratic in the drug dose (7) was used for survival time evaluation and optimal dose calculation. The hazard functions and the index of relative hazard were determined using Weibull distribution after logarithmic transformation of the entered data in each particular group. The dose-response curve was represented by a second-degree polynomial without absolute term. The combination therapy revealed that the optimal dose of ALC was 186 mg/kg s.c. This relation is shown in Fig.1. A significant effect of ALC (s.c.) in combined therapy with MX (6 mg/kg i.v.) given to animals bearing an experimental form of leukemia L1210/MX resistant to MX was proven at a level of probability p < or = 0.001. The effect of ALC in monotherapy was not demonstrable.

Controlled trial of 3-day quinine-clindamycin treatment versus 7-day quinine treatment for adult travelers with uncomplicated falciparum malaria imported from the tropics

We conducted a randomized, double-blind, placebo-controlled trial to compare a 3-day quinine-clindamycin regimen (group QC) with a 7-day quinine regimen (group Q) for the treatment of uncomplicated Plasmodium falciparum malaria in travelers returning from the tropics. A total of 55 and 53 patients in groups Q and QC were analyzed, respectively. Adverse effects were similar in both groups, although two patients in group Q had severe adverse reactions, leading to the cessation of treatment. The 28-day cure rate for the evaluated patients (per-protocol analysis) was 100% for group QC, whereas it was 96.3% for group Q (P = 0.5). The 28-day cure rate in the intention-to-treat analysis was 96.2% for group QC, whereas it was 94.6% for group Q (P = 1). There were no significant differences between the two regimens with regard to parasite and fever clearance times. Our study shows that the 3-day quinine-clindamycin regimen is well tolerated and compares favorably with a 7-day quinine treatment. This short-term regimen had previously been evaluated only in areas of endemicity. According to our results, the 3-day quinine-clindamycin regimen may be an alternative for the treatment of imported uncomplicated P. falciparum malaria in travelers returning from the tropics.

Sex-dependent neutralizing humoral response to Schistosoma mansoni 28GST antigen in infected human populations

The reduction of Schistosoma fecundity observed after experimental vaccination with the Schistosoma mansoni 28-kDa glutathione S-transferase (Sm28GST) antigen has been related to the inhibition of glutathione S-transferase (GST) enzymatic activity by specific antibody. The humoral immune response to the protective antigen Sm28GST and to the epitopes involved in the enzymatic site (amino acid ¿aa sequences 10-43 and 190-211) was evaluated in infected individuals before chemotherapy treatment. The capacity of the serum samples to inhibit GST enzymatic activity was assessed. Specific IgG3 response was predominant in the male population with a low intensity of infection and was associated with maximal GST inhibition. In contrast, the neutralizing activity of serum samples from women with a low intensity of infection was correlated with high specific IgA response specifically directed toward the 190-211 epitope. These results strongly support the hypothesis that GST-neutralizing IgG3 and IgA isotypes are sex dependent. The relationship of this specific acquired immune response with the level of intensity of infection is discussed.

[Serum cortisol level variations in thyroid diseases]

This work studies the thyroid disorders impact on adrenals glands by measuring total cortisol. Radioimmunoassays of thyroid hormones and cortisol were performed in 108 subjects, aged 20-52 years, with thyroid diseases. Our results show low cortisol values (80.35 nmol/L) in 4.77% of hyperthyroids, high values in 3.57% of hyperthyroids (1348.18 nmol/L) and 12.5% of hypothyroids (969.05 nmol/L). In hyperthyroidism, thyroid hormone stimulates the secretion of 11 ceto metabolites biologically inactive, unable to slow pituitary activity, inducing an increased production of endogene cortisol. Excessive catabolism can lead to the exhausting of overstimulated adrenal glands, and therefore to a decreased cortisol. In hypothyroidism, high cortisol results of increase cortisol half life and decrease of metabolic clearance. Control mechanisms often allow normal cortisol values. These alterations in functional activity of adrenal glands, seen in nearly 10% of these subjects, sometimes command a specific attitude in diagnosis and therapy.

Cellular immune responses of a Senegalese community recently exposed to Schistosoma mansoni: correlations of infection level with age and inflammatory cytokine production by soluble egg antigen-specific cells

A recently reported epidemic of Schistosoma mansoni infection in Senegal provided an opportunity to study the dynamics of the development of immunity to human schistosomiasis. We report here on the cell-mediated immune response in a population of 99 females and 95 males, with particular emphasis on the relationship between intensity of infection and age. We found that the intensity of infection correlated negatively with age in females but not in males. In men and women, both Th1- and Th2-type cytokines were detected upon in vitro stimulation of PBMCs with soluble egg antigen (SEA) or soluble adult worm antigens (SWAP). In the female group, SEA-induced PBMC proliferation was associated with the production of IFN-gamma, IL-2 and IL-5, all of which correlated negatively with intensity of infection. Most cytokine production correlated positively with age. Spontaneous production of TNF-alpha, IL-6 and IL-10 was higher in the infected population than in an uninfected control group. Our results suggest that immunity to infection could be more pronounced in the female population and associated with a Th0/1 + 2 pattern of cytokine secretion mediated by soluble egg antigen (SEA).

Epidemic typhus imported from Algeria

We report epidemic typhus in a French patient returning from Algeria. The diagnosis was confirmed by serologic testing and the isolation of Rickettsia prowazekii in blood. Initially the patient was thought to have typhoid fever. Because body lice are prevalent in industrialized regions, the introduction of typhus to pediculosis-endemic areas poses a serious public health risk.

Differential serologic response to Mycoplasma ovipneumoniae and Mycoplasma arginini in lambs affected with chronic respiratory disease

An enzyme-linked immunoabsorbent assay (ELISA) was used to evaluate the levels of antibodies to Mycoplasma ovipneumoniae and M. arginini in lambs with chronic respiratory disease. Sera were obtained from lambs in several flocks at various stages of the clinical disease and tested with sodium dodecyl sulfate (SDS)-treated M. ovipneumoniae and M. arginini whole cells and a crude capsular extract of M. ovipneumoniae as the antigens. There were low levels of antibody to M. ovipneumoniae in flocks sampled at the early stages of infection, whereas increased levels of antibody were present in lambs from flocks that had apparently recovered from the clinical disease. Slowly rising titers of circulating antibodies to M. ovipneumoniae were confirmed by sequential bleeding of lambs during the course of the clinical disease. However, antibody levels of M. arginini were more likely to increase earlier in the disease process. There was significant cross-reactivity between the 2 SDS-treated antigens in both the ELISA test and western immunoblotting. In contrast, the crude capsular extract was specific for detecting antibodies to M. ovipneumoniae.

Occurrence of autoantibodies to cilia in lambs with a 'coughing syndrome'

A respiratory disease of lambs that has been termed the 'coughing syndrome' has been observed in the mid-western region of the United States of America. Mycoplasma ovipneumoniae (M. ovipneumoniae) and Mycoplasma arginini (M. arginini) were routinely isolated from the respiratory tract of lambs with this disease. A high level of antibodies reactive with ovine cilia of the upper respiratory tract was detected in the sera from many of the lambs in affected flocks but not in sera of lambs from unaffected flocks. The reactivity of these antibodies with cilia was demonstrated by ELISA and confirmed by indirect immunofluorescent staining and western immunoblotting. These antibodies were predominantly of the IgG isotype. They were distinct from cold or warm agglutinins and could be absorbed from the sera with cilia but not with antigens of common bacterial pathogens of the sheep respiratory tract including M. ovipneumoniae, M. arginini, Pasteurella haemolytica, Pasteurella multocida or Neisseria ovis. In addition, their occurrence appeared to be independent of the specific antibodies to M. ovipneumoniae and M. arginini. Western immunoblotting indicated that the antibodies were directed primarily against an antigen with apparent molecular weight of 50 kDa. In one flock from which serial serum samples were collected from the same lambs over a 10-month period, antibodies to ovine cilia developed before the onset of the clinical disease and persisted for a period of several months until most of the lambs had apparently recovered. However, colonization of the respiratory tract of the lambs by M. ovipneumoniae preceded the production of these antibodies. Sequential serum samples taken from another flock, with no known history of this coughing, showed no such antibodies throughout the sampling period. It is suggested that an immunopathologic mechanism involving production of autoantibodies directed against a ciliary antigen of the lambs could be a contributing factor to the pathogenesis of this clinical disease.

[Infectious etiology of diarrheal morbidity in a Senegalese region of high exposure to Schistosoma mansoni]

Endemic schistosomiasis due to Schistosoma mansoni has been observed in Richard-Toll (The Senegal River basin) in Senegal since 1990. Because of its high prevalence, schistosomiasis is assumed to be the cause of most cases of diarrhea observed in the region. The purpose of the present study carried out within the framework of the ESPOIR program for control of bilharziasis in the Senegal River region was to confirm the exact etiology of diarrhea in the region. A total of 109 subjects presenting diarrhea including 57 children under the age of 5 years were included in the study. In all cases, stool examination using appropriate techniques was performed to detect bacterial, viral, and parasitic agents. Schistosoma mansoni was identified in 47 cases (43.1%). Stool cultures were positive in 28 cases (25.6%) for Escherichia coli (n = 9), Shigella spp. (n = 18), and Salmonella spp. (n = 1). With regard to Shigella, a predominance of the Shigella dysenteriae type I stereotype (10/18) and a high incidence of co-infection involving Shigella spp. and Schistosoma was noted. Rotavirus infection was observed in 6 cases involving subjects under the age of 5 years. The relative incidence of the different infectious agents varied widely in function of age. This study in an endemic area of bilharziasis in Senegal demonstrates that Schistosoma mansoni should not be assumed to account for all cases of diarrhea occurring in the area.

[Endobronchial tuberculosis presenting as an obstructive tumor in an HIV-1-positive patient. Apropos of a case and review of the literature]

INTRODUCTION

A rare case report of endobronchial tuberculosis is reported in an HIV-1 positive patient of black African origin.

EXEGESIS

A 38-year-old woman of Guinean origin, HIV-1 positive, presented with persistent right upper lobe opacity at chest X-ray. Computerized tomography of the chest after injection confirmed this finding and revealed right laterotracheal and Barety space adenopathy. Investigations of acid-fast bacilli in the biological media were negative. Fiberoptic bronchoscopy showed endobronchial lesion on the wall of the ventral part of the right upper lobe, which had the appearance of bronchogenic carcinoma, and infiltrates in the dorsal mucosa. Biopsy of the lesion revealed granuloma formation, but no evidence of caseation necrosis. Identification of Mycobacterium tuberculosis in sputum culture helped arrive at a diagnosis of endobronchial tuberculosis similar to obstructive bronchial tumor.

CONCLUSION

This case of endobronchial tuberculosis is the first described in an HIV-1 positive patient of black African origin. Mediastinal lymph node revealed by chest computerized tomography after injection could be the site of spreading of mycobacteria by fistulization of tuberculosis lymph node into the right main bronchus. Only the histology of lesions carried out during bronchial fibroscopy permitted the exclusion of endobronchial neoplasia. In addition, the sensitivity of direct microscopy for acid-fast bacilli is poor. Identification of Mycobacterium tuberculosis by sputum culture helped guide the diagnosis which was further confirmed by a good therapeutic response. This case of endobronchial tuberculosis in an immunodepressed patient underlines the difficulty in determining the etiology of pulmonary opacities.

Demonstration of a capsule on Mycoplasma ovipneumoniae

OBJECTIVE

To examine Mycoplasma ovipneumoniae for presence of a capsule and its potential role in adherence.

SAMPLE POPULATION

17 isolates of M ovipneumoniae and 2 isolates of M arginini, recovered from sheep with respiratory tract disease.

PROCEDURE

Mycoplasmas were cultured in modified Fills broth medium, ovine fetal lung cells, or ovine tracheal ring explants. Pelleted mycoplasmas or ring cultures infected with mycoplasmas were treated with ruthenium red or polycationic ferritin and visualized by transmission electron microscopy. Reactivity of several lectins with the mycoplasmas was studied by use of a microtitration plate agglutination test.

RESULTS

Electron microscopy revealed a large number of M ovipneumoniae cells covered with an electron dense-stained amorphous material suggesting that it was a capsule. Multiple passages of the microorganisms in modified Friis broth medium decreased thickness of the capsule, but not percentage of cells encapsulated. Marked differences were observed when M ovipeumoniae isolates grown in modified Friis broth medium or co-cultured with ovine fetal lung cells were compared for capsular thickness or percentage of encapsulation. In thin sections of ruthenium red-stained tracheal ring cultures, the mycoplasmas appeared to be in close contact with cilia through their capsule. All isolates of M ovipneumoniae reacted strongly with wheat germ agglutinin lectin.

CONCLUSIONS

Mycoplasma ovipneumoniae produces a polysaccharide capsule with variable thickness that is dependent on culture conditions and strain. Morphologic observations suggest that this capsule facilitates adherence of the organism to ciliated epithelium.

Human IgE responses to rSm22.6 are associated with infection intensity rather than age per se, in a recently established focus of Schistomiasis mansoni

In studies of schistosomasis mansoni-endemic communities, individuals with IgE responses to a 22 kD adult worm antigen (rSm22.6) suffered lower intensities of reinfection after treatment. It is of interest to define the factors that lead to the production of rSm22.6-specific IgE because it is a marker for resistant individuals and it may be involved in the development of resistance to reinfection. In endemic populations rSm22.6-specific IgE increases linearly with age. However, it is not possible to distinguish between age per se and 'history of infection' in endemic populations because individuals are exposed to the parasite at an early age. We have, therefore, quantified pre- and post-treatment isotype responses to rSm22.6 in a comparatively 'epidemic' Senegalese community where the patients were infected at different ages and where pre-treatment intensity of infection can be taken as a reasonable measure of antigen exposure. Post-treatment isotype responses to rSm22.6 correlated positively with pre-treatment intensities of infection but were not shown to be related to age. IgG1, IgG4 and IgE responses to rSm22.6 were significantly higher after treatment with the difference increasing with the pre-treatment level of infection. These results from a recently established focus of infection suggest that isotype responses to rSm22.6 are antigen-exposure dependent rather than dependent on age per se.

Field isolates of Mycoplasma ovipneumoniae exhibit distinct cytopathic effects in ovine tracheal organ cultures

Ovine tracheal ring explants were infected with four different Mycoplasma ovipneumoniae and one M. arginini field isolate and their ability to induce cytopathic effects was tested by measuring ciliary activity and intracellular calmodulin release. Infected tracheal rings showed significantly decreased ciliary activity as compared to the non-infected control rings. There were, however, marked differences between isolates in the onset and severity of the effects which correlated with their ability to produce hydrogen peroxide. Infected tracheal rings released more calmodulin than the non-infected controls. The amount of calmodulin released also varied between isolates, and somewhat reflected the degree of loss of ciliary activity in the corresponding rings induced by the different isolates. Light and electron microscopic examinations of infected tracheal rings revealed disorganisation and sloughing of the epithelium, and association of mycoplasmas only with the cilia. Following repeated in vitro passages, the organisms had reduced ability to inhibit ciliary activity which correlated with decreased hydrogen peroxide production. Addition of catalase to the organ cultures delayed loss of ciliary activity. These results suggest that M. ovipneumoniae induced ciliostasis in ovine tracheal ring explants which correlated with hydrogen peroxide production. Furthermore, these M. ovipneumoniae-induced injuries to respiratory epithelial cells could contribute to the role that this organism may play in sheep respiratory disease.

Evaluation of ultrasonographic staging systems for the assessment of Schistosoma mansoni induced hepatic involvement

For the sonographic assessment and grading of hepatosplenic morbidity induced by Schistosoma mansoni infection, several quantitative and qualitative classification systems have been used. In an attempt to evaluate two staging systems, a study was performed as part of a schistosomiasis research and control programme in Richard Toll, Senegal. A total of 700 residents of the township N'diangué were parasitologically, clinically and sonographically examined in July 1993. Two ultrasound observers (M.D. and E.D.) applied the Cairo and the Managil classification (E.D. only) for the grading of periportal thickening of the liver. In spite of high prevalence and intensity of infection, severe hepatic morbidity was rare. According to the Cairo classification, there was a high percentage of subjects with grade I periportal thickening, with considerable inter-observer variability. In the Cairo classification, which is based on the diameter of peripheral portal vein branches, firm cut-offs are used, independent of body height. We show the relationship between body height and portal vein diameters and recommend the use of body height-dependent reference values to avoid falsely high percentages of periportal thickening, especially in children. To minimize inter-observer variability, a clarification of existing instructions for taking measurements for grading is suggested. These suggestions have been considered during the follow-up expert meeting on the Cairo classification in Niamey under the auspices of the World Health Organization in October 1996.

Expression of functions by normal sheep alveolar macrophages and their alteration by interaction with Mycoplasma ovipneumoniae

Normal sheep alveolar macrophages collected by bronchial lavage were exposed to live or heat-killed Mycoplasma ovipneumoniae organisms, and their capability to ingest Staphylococcus aureus and to elicit antibody-dependent cellular cytotoxicity against sensitized chicken red blood cells was tested. Controls consisted of non-infected macrophages in M199 medium. In addition, the effect of M. ovipneumoniae on expression of surface molecules on these sheep alveolar macrophages was determined. The percentage of S. aureus ingested by nontreated sheep alveolar macrophages was significantly higher than that of infected macrophages. Live mycoplasmas were more effective in suppressing the ingestion of S. aureus by these macrophages than killed mycoplasmas. Both live and killed mycoplasmas suppressed the cytolytic effect of the sheep alveolar macrophages to a similar degree. About 78% and 45% of the normal sheep alveolar macrophages had IgG and complement receptors, respectively. Infection of these macrophages with M. ovipneumoniae decreased significantly the expression of IgG receptors but had no effects on complement receptors. There were substantial increases in the expression of both MHC class I and class II by the mycoplasma-induced macrophages as compared with unstimulated macrophages. Live mycoplasmas were more effective in inducing expression of both classes than killed mycoplasmas. The results, taken together, suggest that M. ovipneumoniae induced alterations in macrophage activities and this may be a contributing factor in the pathogenesis of respiratory disease induced by the organism.

Organometric investigations of the spleen and liver by ultrasound in Schistosoma mansoni endemic and nonendemic villages in Senegal

With the intention of ultrasonographically assessing hepatosplenic morbidity in Schistosoma mansoni infection and of validating the grading system applied (Cairo classification), 191 subjects in a schistosomiasis endemic village and 247 controls from a nonendemic village in northern Senegal underwent sonographic examination of the liver and spleen. Measurements of the diameters of the peripheral periportal vein branches, the main portal vein stem, liver size (left lobe and right lobe), and spleen length in the endemic village were compared with those in the nonendemic village to evaluate the much discussed influence of S. mansoni infection on those variables. To subtract this presumed influence from reference values for the named variables, they are given as measured in the nonendemic village, stratified by body weight, enabling future investigators on schistosomiasis-induced morbidity to refer to these reference values. The 95th percentile regarding peripheral periportal vein branch diameter in the control groups was exceeded in 24% of the subjects in the endemic group. It was exceeded by 6% for the main portal vein stem diameter, 13% for the left liver lobe, 12% for the right liver lobe, and 14% for the spleen length. According to the Cairo classification, 97% of the endemic population and 81% of the controls had periportal thickening of the liver, mostly grade I. We conclude that 1) hepatic morbidity in the S. mansoni endemic area was low, despite strikingly high intensities of infection; 2) the Cairo classification in its present form overestimates periportal thickening, especially in the case of mild morbidity; and 3) body height-dependent reference values, obtained from endemic controls, must be applied for organometric parameters.

Oxamniquine cures Schistosoma mansoni infection in a focus in which cure rates with praziquantel are unusually low

An outbreak of Schistosoma mansoni in northern Senegal was observed in 1988, and chemotherapy with praziquantel in this recently established focus resulted in very low parasitologic cure rates. Among other explanations, the emergence of a praziquantel-tolerant parasite strain was feared. To study this hypothesis further, 138 persons with endemic S. mansoni infection were randomly allocated to treatment with either 20 mg/kg oxamniquine or 40 mg/kg praziquantel. Parasitologic cure rates at 6 weeks were significantly higher in the oxamniquine group (79%) compared with those in the praziquantel group (36%; P = .0043). The reduction in egg counts was generally good, but 12% less reduced in the praziquantel group. These results confirm that cure rates with praziquantel were abnormally low, whereas oxamniquine performed satisfactorily, as in other areas in which S. mansoni is endemic. The possibility of a praziquantel-tolerant S. mansoni strain must therefore be studied carefully.

Schistosoma mansoni: maturation rate and drug susceptibility of different geographic isolates

The fecundities and drug susceptibilities of Schistosoma mansoni isolates from Senegal, Puerto Rico, and Kenya have been examined in mice. The Senegal parasite, obtained from the field in 1993, was shown to have a longer prepatent period (eggs first recovered in the faeces on Day 46 after infection) than those of two isolates, from Puerto Rico and Kenya, that had been maintained for a long period in the laboratory (faecal eggs recovered on Days 38 and 36 after infection, respectively). A Kenyan isolate, also collected from the field in 1994, was shown to mature more slowly than the laboratory-maintained Kenyan isolate. Tissue egg counts confirmed that early in infection the fecundity of the recently collected isolates from Senegal and Kenya was significantly lower than that of the long-term laboratory-maintained Kenyan isolate. Praziquantel and oxamniquine treatment of 8-week-old infections caused a significant (P < 0.001) reduction in worm burden in all isolates tested. However, the reduction in worm burden after praziquantel treatment of infections of the Senegal isolate (50% reduction) was significantly lower than the > 90% reductions in worm burdens after praziquantel treatment of mice infected with either of the Kenyan isolates (P < 0.001). The study confirms that despite being tolerant to praziquantel, the Senegal isolate is fully susceptible to oxamniquine. The praziquantel tolerance of the Senegal parasite is not solely attributed to the state of maturation of the parasite at the time of drug administration.

Therapeutic evaluation of two different dose regimens of praziquantel in a recent Schistosoma mansoni focus in Northern Senegal

A therapeutic trial, involving 130 Schistosoma mansoni-infected children, with no previous history of antischistosomal treatment, was carried out to evaluate the efficacy of two different dose regimens of praziquantel. The study was carried out because low cure rates were described in this recently established (1990) S. mansoni focus in northern Senegal, following treatment with a standard dosage of 40 mg/kg. The subjects were randomly allocated into two groups: one group (1) received 40 mg/kg in one oral dose, the other group (2) was treated with two oral doses of 30 mg/kg at a 6-hr interval. Parasitologic examination and circulating anodic antigen (CAA) detection were performed before, 10 days, three, six, and 21 weeks after chemotherapy. No significant differences in cure rates were found between the two groups. Six weeks after treatment, 34% and 44% of the individuals were found to be stool negative in group 1 and group 2, respectively. However, only 10-15% became completely negative according to the serum CAA antigen assay. Mean egg counts were reduced by 99% in both groups. Antigen detection confirmed the parasitologic results. Fewer side effects were observed in the group treated with 2 x 30 mg/kg, which may be explained by split dosage administration. Our study shows that the low cure rates observed in this area could not be improved by using a higher dosage of praziquantel.

Royal Society of Tropical Medicine and Hygiene meeting at Manson House, London, 18 May 1995. The epidemiology of human schistosomiasis in the Senegal river basin

Extensive water development has taken place in the north of Senegal over the last decade, resulting in a large increase in the amount of fresh water for irrigation. The objectives of the present study were to determine the prevalence and intensity of Schistosoma mansoni and S. haematobium in the Senegal river basin (SRB), and to ascertain the distribution of the snail species acting as intermediate hosts for both species of schistosomes. The schistosomiasis survey started in January 1994 and was completed in March 1995. Compared to studies before the construction of the Diama dam, there was a significant increase in both the prevalence and intensity of urinary and intestinal schistosomiasis in the human population in parts of the SRB. From the 9014 people who were registered from 180 villages and 4 towns (10 districts), 7750 were examined. S. mansoni was found in the lower valley (lower delta-Senegal river, lower delta-Lampsar river, upper delta, and diéré) but not in the middle valley. The mean prevalence ranged from 4.4% in the lower delta-Senegal River to 71.8% in the zone of Lac de Guiers, where prevalence and intensity of infection were higher on the eastern side of the lake (81.3% with a mean number of 2088 eggs/g of faeces) compared with the western side (50.3% with a mean 1111 eggs/g). S. haematobium was recorded throughout the area of study, ranging from a mean prevalence of 0.37% in diére (lower valley) to 41.5% in the lower valley (Lampsar river), where the mean egg count was 313/10 mL of urine. Physical and chemical changes to the environment have favoured the spread and increase in the populations of freshwater snails. The only snail involved in the transmission of S. mansoni was Biomphalaria pfeifferi. Five species of bulinid snails were present--Bulinus globosus, Bu. umbilicatus, Bu. senegalensis, Bu. forskalii and Bu. truncatus--but only the first 3 species were involved in the transmission of S. haematobium in the lower and middle valleys.