A multi-site cross-sectional study on the burden of SARS-CoV-2 in healthcare workers in Madagascar.

The prevalence of infections and risk factors that go along with them give insights into the burden of disease and effectiveness of infection prevention and control strategies. In this study we investigated the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and associated epidemiological factors in three regions of Madagascar among healthcare workers. Between May and June 2021, we conducted a multi-site cross-sectional study among healthcare workers in eight University Hospital Centers, during the local second wave and before the coronavirus disease 2019 vaccination campaign in three regional capitals of Madagascar. We collected demographic information and relevant SARS-CoV-2 exposure history and tested for both immunoglobulin G antibodies to SARS-CoV-2 spike protein, using enzyme-linked immunosorbent assay and active SARS-CoV-2 infection using real-time reverse transcription-polymerase chain reaction. A total of 1006 healthcare workers enrolled in the study out of which 53.8% tested positive for either acute infection or SARS-CoV-2 antibodies. Approximately 50% of the participants reported receiving inadequate training on SARS-CoV-2 and associated infection prevention and control measures, inadequate supply of Personal Protective Equipment (PPE) and discomfort when using available PPE. Prevalence of acute infection was 3.4% without statistically significant variation in the different regions or health facilities as well as the different profession groups and units of work. Average seroprevalence of SARS-CoV-2 IgG antibodies was 52.0%, varying between 47.8% and 53.3% across the different regions. No significant difference was observed for region, gender, profession, and different risk groups. Predictive multivariable model showed significant association between seropositivity and healthcare facility and age (p<0.05). Our results revealed high infection rate of SARS-CoV-2 in HCWs in all three selected regions of Madagascar. The high disease burden identified in the study population might characterize the extent of high undocumented infection rates in HCWs in other regions of Madagascar.

Evaluation of antigen-based rapid detection test for the diagnosis of SARS CoV-2 in low-income countries.

BACKGROUND: In the context of the Covid-19 pandemic and following the increasing number of suspicious Covid-19 cases in Madagascar, Malagasy laboratories are overflowed mainly due to lack of human resource and available material restriction. The development and validation of rapid and easy-to-perform diagnostic methods are worth of interest and high priority. The aim of this prospective study was to evaluate the performances of a rapid immunochromatographic test for the detection of SARS-CoV-2 antigen, in comparison to Reverse transcription polymerase chain reaction (RT-PCR). METHODS: The fluorescence immunochromatographic SARS-CoV-2 antigen test StandardTM Q COVID-19 Ag Test (SD Biosensor Republic Korea) was evaluated in samples derived from patients who were examined for disease categories. Diagnostic accuracy was determined in comparison to SARS-CoV-2 RT-PCR considered as gold standard. RESULTS: A total of 200 samples were included; 94 were RT-PCR positive. Median patients' age was 38.36 years, 63.5 % were male. Overall sensitivity and specificity of the Standard TM Q COVID-19 Ag (SD Biosensor® Republic Korea) were 62.66 % and 100 %, the sensitivity was significantly higher (100 %) in samples with high viral loads (Ct<29). CONCLUSIONS: This antigen-based immunofluorescence RDT could be the potential to become an important tool for the early diagnosis of SARS-CoV-2 particularly in situations with limited access to molecular methods particularly in rural area of Madagascar.

Cell-type- and region-specific modulation of cocaine seeking by micro-RNA-1 in striatal projection neurons.

The persistent and experience-dependent nature of drug addiction may result in part from epigenetic alterations, including non-coding micro-RNAs (miRNAs), which are both critical for neuronal function and modulated by cocaine in the striatum. Two major striatal cell populations, the striato-nigral and striato-pallidal projection neurons, express, respectively, the D1 (D1-SPNs) and D2 (D2-SPNs) dopamine receptor, and display distinct but complementary functions in drug-evoked responses. However, a cell-type-specific role for miRNAs action has yet to be clarified. Here, we evaluated the expression of a subset of miRNAs proposed to modulate cocaine effects in the nucleus accumbens (NAc) and dorsal striatum (DS) upon sustained cocaine exposure in mice and showed that these selected miRNAs were preferentially upregulated in the NAc. We focused on miR-1 considering the important role of some of its predicted mRNA targets, Fosb and Npas4, in the effects of cocaine. We validated these targets in vitro and in vivo. We explored the potential of miR-1 to regulate cocaine-induced behavior by overexpressing it in specific striatal cell populations. In DS D1-SPNs miR-1 overexpression downregulated Fosb and Npas4 and reduced cocaine-induced CPP reinstatement, but increased cue-induced cocaine seeking. In DS D2-SPNs miR-1 overexpression reduced the motivation to self-administer cocaine. Our results indicate a role of miR1 and its target genes, Fosb and Npas4, in these behaviors and highlight a precise cell-type- and region-specific modulatory role of miR-1, illustrating the importance of cell-specific investigations.

Cell-Type-Specific Adaptions in Striatal Medium-Sized Spiny Neurons and Their Roles in Behavioral Responses to Drugs of Abuse.

Drug addiction is defined as a compulsive pattern of drug-seeking- and taking- behavior, with recurrent episodes of abstinence and relapse, and a loss of control despite negative consequences. Addictive drugs promote reinforcement by increasing dopamine in the mesocorticolimbic system, which alters excitatory glutamate transmission within the reward circuitry, thereby hijacking reward processing. Within the reward circuitry, the striatum is a key target structure of drugs of abuse since it is at the crossroad of converging glutamate inputs from limbic, thalamic and cortical regions, encoding components of drug-associated stimuli and environment, and dopamine that mediates reward prediction error and incentive values. These signals are integrated by medium-sized spiny neurons (MSN), which receive glutamate and dopamine axons converging onto their dendritic spines. MSN primarily form two mostly distinct populations based on the expression of either DA-D1 (D1R) or DA-D2 (D2R) receptors. While a classical view is that the two MSN populations act in parallel, playing antagonistic functional roles, the picture seems much more complex. Herein, we review recent studies, based on the use of cell-type-specific manipulations, demonstrating that dopamine differentially modulates dendritic spine density and synapse formation, as well as glutamate transmission, at specific inputs projecting onto D1R-MSN and D2R-MSN to shape persistent pathological behavioral in response to drugs of abuse. We also discuss the identification of distinct molecular events underlying the detrimental interplay between dopamine and glutamate signaling in D1R-MSN and D2R-MSN and highlight the relevance of such cell-type-specific molecular studies for the development of innovative strategies with potential therapeutic value for addiction. Because drug addiction is highly prevalent in patients with other psychiatric disorders when compared to the general population, we last discuss the hypothesis that shared cellular and molecular adaptations within common circuits could explain the co-occurrence of addiction and depression. We will therefore conclude this review by examining how the nucleus accumbens (NAc) could constitute a key interface between addiction and depression.

Npas4 regulates medium spiny neuron physiology and gates cocaine-induced hyperlocomotion.

We show here that the transcription factor Npas4 is an important regulator of medium spiny neuron spine density and electrophysiological parameters and that it determines the magnitude of cocaine-induced hyperlocomotion in mice. Npas4 is induced by synaptic stimuli that cause calcium influx, but not dopaminergic or PKA-stimulating input, in mouse medium spiny neurons and human iPSC-derived forebrain organoids. This induction is independent of ubiquitous kinase pathways such as PKA and MAPK cascades, and instead depends on calcineurin and nuclear calcium signalling. Npas4 controls a large regulon containing transcripts for synaptic molecules, such as NMDA receptors and VDCC subunits, and determines in vivo MSN spine density, firing rate, I/O gain function and paired-pulse facilitation. These functions at the molecular and cellular levels control the locomotor response to drugs of abuse, as Npas4 knockdown in the nucleus accumbens decreases hyperlocomotion in response to cocaine in male mice while leaving basal locomotor behaviour unchanged.

Disrupting D1-NMDA or D2-NMDA receptor heteromerization prevents cocaine's rewarding effects but preserves natural reward processing.

Addictive drugs increase dopamine in the nucleus accumbens (NAc), where it persistently shapes excitatory glutamate transmission and hijacks natural reward processing. Here, we provide evidence, from mice to humans, that an underlying mechanism relies on drug-evoked heteromerization of glutamate N-methyl-d-aspartate receptors (NMDAR) with dopamine receptor 1 (D1R) or 2 (D2R). Using temporally controlled inhibition of D1R-NMDAR heteromerization, we unraveled their selective implication in early phases of cocaine-mediated synaptic, morphological, and behavioral responses. In contrast, preventing D2R-NMDAR heteromerization blocked the persistence of these adaptations. Interfering with these heteromers spared natural reward processing. Notably, we established that D2R-NMDAR complexes exist in human samples and showed that, despite a decreased D2R protein expression in the NAc, individuals with psychostimulant use disorder display a higher proportion of D2R forming heteromers with NMDAR. These findings contribute to a better understanding of molecular mechanisms underlying addiction and uncover D2R-NMDAR heteromers as targets with potential therapeutic value.

Decline in Vaccine-Type Streptococcus pneumoniae Serotypes Following Pneumococcal Conjugate Vaccine Introduction in Madagascar.

BACKGROUND: The 10-valent conjugate vaccine (PCV10) was introduced into the Extended Program on Immunization in Madagascar. We assessed the impact of PCV10 on the targeted pneumococcal serotypes among children < 5 years of age at Centre Hospitalier Universitaire Mère Enfant Tsaralalàna. METHOD: Between 2012 and December 2018, cerebrospinal fluid (CSF) samples were collected and tested for S. pneumoniae by culture, and antigen tests. The Sentinel Site Laboratory (SSL) referred available CSF samples to the Regional Reference Laboratory (RRL) for real-time polymerase chain reaction confirmatory testing and serotyping. RESULTS: In total, 3616 CSF specimens were collected. The SSL referred 2716 to the RRL; 125 were positive for S. pneumoniae. At the RRL, 115 samples that tested positive for S. pneumoniae were serotyped; PCV10 serotypes accounted for 20%. Compared to the pre-PCV period, the proportion of S. pneumoniae detected declined from 22% to 6.6%, (P < .05), the proportion of PCV10 serotypes as the cause of pneumococcal meningitis cases declined by 26% following vaccine introduction. CONCLUSIONS: In our findings, PCV10 introduction resulted in a decline of meningitis caused by S. pneumoniae and PCV10 vaccine serotypes.

Modulation and functions of dopamine receptor heteromers in drugs of abuse-induced adaptations.

Drug addiction is a chronic and relapsing disorder that leads to compulsive drug intake despite deleterious consequences. By increasing dopamine (DA) in the mesolimbic system, drugs of abuse hijack the brain reward circuitry, which is critical for the development of enduring behavioral alterations. DA mainly acts onto DA D1 (D1R) and D2 (D2R) receptor subtypes, which are positively and negatively coupled to adenylyl cyclase, respectively. Extensive research has aimed at targeting these receptors for the treatment of addiction, however this often results in unwanted side-effects due to the implication of DA receptors in numerous physiological functions. A growing body of evidence indicates that the physical interaction of DA receptors with other receptors can finely tune their function, making DA receptor heteromers promising targets for more specific treatment strategies. An increasing number of articles highlighted the ability of both D1R and D2R to form heteromers, however, most studies carried out to date stem from observations in heterologous systems and the biological significance of DA receptor heteromers in vivo is only emerging. We focused this review on studies that were able to provide insights into functions on D1R and D2R heteromers in drug-evoked adaptations and discuss the limitations of current approaches to study receptor heteromers in vivo. This article is part of the Special Issue entitled 'Receptor heteromers and their allosteric receptor-receptor interactions'.

Trichomonas vaginalis among women raped in Antananarivo, 2005-2011.

Rape is a forensic emergency due to the possibility of sexually transmitted infections, including HIV/AIDS. Moreover, an upsurge is currently underway. The objective of this study was to determine the incidence of Trichomonas vaginalis in women undergoing tests at the Microbiology Unit of the Joseph Ravoahangy Andrianavalona Antananarivo Hospital after being raped. This retrospective descriptive study covers the 7-year period from 2005 to 2011 and reports the results of direct examination of the vaginal discharge after vulvar smears from rape patients. We studied the age of patients and the results of these direct smear examinations that tested for T. vaginalis. In our study, the number of women with T. vaginalis increased markedly with age. The mean age of the patients was 13.7 years (range: 2 to 41 years). Among the 232 rape victims tested, only 26 were positive for it (11.20%); trichomoniasis was thus rare among these women. T. vaginalis is a common cause of vaginitis in women and one of the most common infections transmitted by sexual assault. In children, the presence of T. vaginalis in vaginal sample is a strong indicator of sexual abuse. Other sexually transmitted infections can be transmitted during sexual abuse.