Peste Des Petits Ruminants in Benin: Persistence of a Single Virus Genotype in the Country for Over 42 Years

Peste des petits ruminants (PPR) is a contagious and often fatal disease affecting sheep and goats. Currently, it is endemic in Africa, the Middle and Near East, the Indian subcontinent and China. Understanding the molecular epidemiology and evolution of PPR virus (PPRV) can assist in the control of the transboundary spread of this economically important disease. We isolated PPRV from pathological and swab samples collected 42 years apart (1969 and 2011) in Benin, West Africa, and sequenced the full genome of two isolates (Benin/B1/1969 and Benin/10/2011). Phylogenetic analysis showed that all of the characterized isolates clustered within viral lineage II and that the 2011 isolates fell into two distinct subgroups. Comparison of the full genome sequences revealed a 95.3% identity at the nucleotide level, while at the protein level, the matrix protein was the most conserved between the two viruses with an identity of 99.7% and only one amino acid substitution over the 42‐year sampling period. An analysis of specific amino acid residues of known or putative function did not identify any significant changes between the two viruses. A molecular clock analysis of complete PPRV genomes revealed that the lineage II viruses sampled here arose in the early 1960s and that these viruses have likely persisted in Benin since this time.     

Clinical, biological and radiological spectrum of newly diagnosed pulmonary tuberculosis

The aim of the present study was to describe the clinical, biological and the chest-X ray presentations of newly diagnosed pulmonary tuberculosis. A retrospective study of 200 patients was performed from January to October 2004 in the respiratory diseases unit of Dakar's University Teaching Hospital. Among the 200 cases, 140 (70%) were male, giving a sex ratio of 2.3. The mean age of our patients was 35.5 years (range: 14-81 years). The group age of 20 to 39 years was the most affected (55,5% of patients). The median diagnostic delay was 4 months (range: 7 days to 2 years). Haemoptysis revealed the disease in 27% of cases. The chest X-ray showed bilateral lesions in 65% of cases. When they were unilateral, the right side was the most concerned. Of the 200 patients, the lesions interested all parts of at least one lung in 106 (53%). Among our patients, 153 (76.5%) had cavitations and 145 (72.5%) had infiltrates. A pleural effusion was associated to the lung lesions in 10% of the patients. Biologically, we reported 80% cases (n=160) of hypochromic microcytic anaemia. Of the 27 HIV tests done, 18 (66.7%) were positive all for HIV1. Delay in the diagnosis of pulmonary tuberculosis was very long and our data illustrate the need for improved education of the community and event of healthcare workers about the benefit of early diagnosis of tuberculosis.     

Hematologic abnormalities and immunodepression in HIV/AIDS- related pulmonary tuberculosis]

Our objectives were to describe hemato-immunological abnormalities encountered in tuberculosis patients HIV seropositive (TBVIH+, n = 67) or not (TBVIH-, n = 39) and in HIV asymptomatic patients (aSVIH+, n = 40). We found: a great reduction of mean value of RBC and Hb in TBVIH+ and TBVIH-; a reduction of mean value of leucocytes, total lymphocytes and CD4+ lymphocytes in TBVIH+ and aSVIH+; an inversion of [formula: see text] ratio, more important in TBVIH+ than in aSVIH+. HIV and tuberculosis association, HIV1 serotype and CD4 < 200/mm3 were found to promote significantly hemato-immunological abnormalities.     

Spillover,hybridization, and persistence in schistosome transmission dynamics at the human–animal interface

Zoonotic spillover and hybridization of parasites are major emerging public and veterinary health concerns at the interface of infectious disease biology, evolution, and control. Schistosomiasis is a neglected tropical disease of global importance caused by parasites of the Schistosoma genus, and the Schistosoma spp. system within Africa represents a key example of a system where spillover of animal parasites into human populations has enabled formation of hybrids. Combining model-based approaches and analyses of parasitological, molecular, and epidemiological data from northern Senegal, a region with a high prevalence of schistosome hybrids, we aimed to unravel the transmission dynamics of this complex multihost, multiparasite system. Using Bayesian methods and by estimating the basic reproduction number (R₀), we evaluate the frequency of zoonotic spillover of Schistosoma bovis from livestock and the potential for onward transmission of hybrid S. bovis × S. haematobium offspring within human populations. We estimate R₀ of hybrid schistosomes to be greater than the critical threshold of one (1.76; 95% CI 1.59 to 1.99), demonstrating the potential for hybridization to facilitate spread and establishment of schistosomiasis beyond its original geographical boundaries. We estimate R₀ for S. bovis to be greater than one in cattle (1.43; 95% CI 1.24 to 1.85) but not in other ruminants, confirming cattle as the primary zoonotic reservoir. Through longitudinal simulations, we also show that where S. bovis and S. haematobium are coendemic (in livestock and humans respectively), the relative importance of zoonotic transmission is predicted to increase as the disease in humans nears elimination.

There is a growing acknowledgment of the profound threat that zoonoses (diseases transmitted between animals and humans) pose to human health worldwide, with animal reservoirs presenting diverse complications to elimination efforts for many existing diseases, as well as novel threats in the form of newly emerging diseases (1, 2). Global trends such as increased migration, altering agricultural practices, and a changing climate are all predicted to enhance the potential for human and animal populations to encounter new infectious agents, thereby also increasing opportunities for coinfection by multiple pathogen species within the same host (3–7). Such mixed infections can lead to exchange of genetic material between the coinfecting agents, generating new pathogen genotypes. In the case of helminth parasites which sexually reproduce, this can occur through heterospecific (between-species) mate pairings (8, 9), which can lead to the formation of hybrid offspring (9, 10). Hybridizations, as well as subsequent introgressions (the introduction of single genes or chromosomal regions from one species into another through repeated backcrossing), represent an additional source of genetic variation that may drive parasite evolution, with potential implications including increased host and geographical range, altered pathology, resistance to drug therapy, and, ultimately, persistence in the face of elimination efforts (9). The presence of interspecific hybridizations and introgressions brings an increased level of complexity to disentangling the transmission dynamics of multihost systems, requiring multimodal and original approaches and necessitating data from across disciplines and scales—from the molecular to the population level (11).The significance of zoonotic transmission and parasite hybridization is exemplified by the case of schistosomiasis. Schistosomiasis is a neglected tropical disease estimated to infect over 220 million people, over 90% of whom reside in sub-Saharan Africa (12–14). The disease is caused by parasites of the Schistosoma genus, which have a complex life cycle that includes sexual reproduction in a mammalian definitive host and indirect transmission via a freshwater snail intermediate host. The schistosome species Schistosoma haematobium (the causative agent for urogenital schistosomiasis in people) has been demonstrated to form viable hybrids and introgressions with closely related schistosome species of the larger Haematobium group which infect livestock, notably Schistosoma bovis, Schistosoma curassoni, and Schistosoma mattheei (causative agents of intestinal schistosomiasis in livestock) (15–20). Hybrids between S. haematobium and S. bovis have been reported in human patients across sub-Saharan Africa, including Senegal, Niger, Côte d’Ivoire, and Mali (21–23), as well as in the recent outbreaks of schistosomiasis in Corsica (24, 25). One recent study in northern Senegal, a region where both S. haematobium and S. bovis are coendemic, indicated that ongoing pairing between these two species leads to creation of hybrids in human hosts and is occurring here via zoonotic spillover of S. bovis from a livestock reservoir to people who are simultaneously infected with S. haematobium (19). Spillover is defined as transmission, from a reservoir to a defined target host, of a pathogen that cannot normally be sustained within the target host population (26, 27), while reservoirs are defined as one or more populations in which a pathogen can be maintained and from which infection is transmitted to a defined target population (28). While molecular data from the study in Senegal indicated that S. bovis cannot be maintained by the human population (hence fitting the definition for a spillover pathogen), onward transmission of hybrids was shown to occur within the human population via backcrossing and introgressions, leading to a complex array of observed miracidia genotypes (miracidia being the first larval schistosome stage which hatches from eggs shed by an infected host) from human specimens.The public health impact of zoonotic spillover is fundamentally determined by the force of infection from the reservoir species and the potential for onward transmission and persistence within the human population (29), with identification of key hosts and reservoirs also critical to our understanding of multihost systems. These aspects of transmission are crucial for determining appropriate targets for interventions, and ultimately the feasibility of disease elimination, yet are often little-studied and poorly understood.Given that formation of F1 hybrids requires a host to be simultaneously infected with S. haematobium and S. bovis, attention is naturally focused on geographic localities where circulation of these two closely related schistosome species may be sympatric. It has remained unclear whether humans can act as maintenance hosts for these hybrid parasites after they have been generated by the initial cross-species pairing, or if ongoing zoonotic spillover is required for hybrids to persist in the human population. The fact that hybrid schistosomes identified in the Corsican outbreak were found to have been imported from Senegal (25) highlights both the need to understand the zoonotic potential of S. bovis and, crucially, to evaluate the potential for hybridization to facilitate spread and establishment of schistosomiasis beyond its original geographical boundaries.Here we combine mathematical modeling and statistical approaches with molecular and epidemiological data from a recent study in northern Senegal (19) in order to evaluate the spillover and multihost dynamics within the Haematobium group hybrid schistosome system. We examine the relative importance of zoonotic spillover in maintaining transmission both at current levels of endemicity and in scenarios where the human disease may be nearing elimination and characterize the relative role of the livestock species involved in zoonotic transmission. Model structure was informed by the insights from the molecular data and parameterized using Bayesian approaches, with output then applied to existing frameworks for classifying multihost systems and zoonotic disease threats (26, 27, 29). This included estimation of the basic reproduction number, or R_0, within each host species. Given the lack of literature on key aspects of S. bovis biology necessary for fitting the model to observable data, we also describe a Bayesian approach for inferring the relationship between worm burden and fecal egg count using postmortem studies of naturally occurring infections. We explore the potential for density-dependent effects in this relationship and consider the implications of such effects for macroparasite transmission dynamics in general.With current trends in anthropogenic activities predicted to drive infectious disease emergence at the global scale, integrative methods for characterizing pathogen transmission events at the animal–human interface and evaluating the consequences of novel pathogen interactions, including hybridizations, have been identified as key scientific challenges (9, 30, 31). As we seek to understand increasingly complex disease dynamics, our work will therefore be of relevance not only for the control of schistosomiasis but also for a growing number of disease systems in our rapidly changing world.     

Treatment of status epilepticus in a developing country]

Status epilepticus (SE) is a condition requiring emergency care, which is often poorly managed in developing countries due to the lack of personnel, drugs, and insufficient technical and medical means. This study aims at determining the epidemiologic and etiologic characteristics and the difficulty in treating SE under the existing medical practice conditions in a developing country such as Senegal. A retrospective study was therefore carried out based on SE medical files at the University Hospital of Dakar over the period January 1988 to December 1998, and included several hospital departments, i.e., paediatrics, infectious diseases and neurology. Over an 11-year period 697 cases were recorded; of these, 48.2% of patients were under 5 years of age. The seizures were generalized in 58.2% of cases, partial in 21.2%, partial secondarily generalized, or with an association of both clinical presentations in 20.6% of cases. The etiology was as follows: mainly infectious (67%), followed by resistant and/or unbalanced epilepsy (9.9%), epilepsy of vascular origin (8%), and various other causes. The overall mortality rate was 24.8%. A long period between the onset of clinical symptoms and hospital treatment was noted, with an average time lapse of 16.6 h before treatment. The drugs utilized were diazepam and phenobarbitol, administered by injection. The overall outcome could be improved by better management, i.e., better prevention and an efficient treatment of infectious diseases, a reduction in the time before treatment, and improved means of intensive care.     

Decentralizing postabortion care in Senegal with misoprostol for incomplete abortion

Objective

To expand access to postabortion care (PAC) services in Senegal by introducing misoprostol as a first-line treatment at the community level.

Methods

The present prospective study enrolled 481 women seeking treatment for incomplete abortion at 11 community health posts in Senegal between September 2011 and August 2012. Participants were given 400 μg of sublingual misoprostol and asked to return to the clinic 1 week later to confirm clinical status. At study completion, all women were asked to respond to a series of questions regarding their experience with this method. All care was provided by nurse midwives.

Results

All but three of the study women (99.4%; 474/477) had successful complete abortion after taking misoprostol. Almost all women were satisfied or very satisfied with the treatment (99.6%; 469/471), would select the method again if needed (98.9%; 465/470), and would recommend the method to a friend (99.8%; 468/469).

Conclusion

The results provide further evidence that 400 μg of misoprostol is highly effective for first-line treatment of incomplete abortion. Furthermore, this regimen can be fully provided by nurse midwives, and can be easily and successfully introduced in community health settings where other methods of PAC may not previously have been available. Clinicaltrials.gov: NCT01939457