Epidemiology of adult meningitis during antiretroviral therapy scale-up in southern Africa: Results from the Botswana national meningitis survey

Computed Tomography of the Head Before Lumbar Puncture in Adults With Suspected Meningitis in High-HIV Prevalence Settings

Background

The role of computed tomography (CT) before lumbar puncture (LP) is unclear, with limited evidence for a causal link between LP and cerebral herniation or for the ability of CT to identify individuals at risk of herniation. The risks of LP delay or deferral are potentially greater in high-HIV prevalence, resource-limited settings; we analyzed data from such a setting to determine the impact of CT on time to LP and treatment, as well as mortality.

Methods

Adults with suspected central nervous system (CNS) infection were enrolled prospectively into the Botswana National Meningitis Survey between 2016 and 2019. Inpatient mortality and clinical data including time of treatment initiation and CT were captured from medical records. Associations between preceding CT and outcomes were assessed using logistic regression.

Results

LPs were performed in 711 patients with suspected CNS infection; 27% had a CT before LP, and 73% were HIV positive. Time from admission to LP and time from admission to appropriate treatment were significantly longer in patients who had a CT before LP compared with those who did not (2.8 hours and 13.2 hours, respectively). There was some evidence for treatment delays being associated with increased mortality; however, there was no significant difference in mortality between those who had or did not have CT.

Conclusions

Patients who had a CT had delays to diagnostic LP and initiation of appropriate treatment; although treatment delays were associated with increased mortality, our observational study could not demonstrate a causal association between delays in diagnosis and treatment introduced by CT and mortality.

The Impact of GeneXpert Cerebrospinal Fluid Testing on Tuberculous Meningitis Diagnosis in Routine Care in Botswana

Background

Tuberculous meningitis (TBM) disproportionately impacts high-HIV prevalence, resource-limited settings where diagnosis is challenging. The GeneXpert platform has utility in TBM diagnosis, but uptake remains limited. In Botswana, before the introduction of GeneXpert, tuberculosis (TB) testing was only available through mycobacterial culture at the National TB Reference Laboratory. Data describing routine use of Xpert MTB/RIF for cerebrospinal fluid (CSF) testing in resource-limited settings are scarce.

Methods

Electronic records for patients with CSF tested in government facilities in Botswana between 2016 and 2022 were obtained from a central online repository as part of ongoing national meningitis surveillance. Samples were excluded from 1 site where Xpert MTB/RIF is performed universally. The proportion receiving TB-specific investigation on CSF and the number positive for Mycobacterium tuberculosis following increased Xpert MTB/RIF capacity were determined.

Results

The proportion of CSF samples receiving TB-specific investigation increased from 4.5% (58/1288) in 2016 to 29.0% (201/693) in 2022, primarily due to increased analysis with Xpert MTB/RIF from 0.9% (11/1288) to 23.2% (161/693). There was an overall decline in the annual number of CSF samples analyzed, but the proportion with microbiologically confirmed TBM increased from 0.4% to 1.2%. The proportion of samples tested for TB that were collected from health care facilities >100 km from the National TB Reference Laboratory increased with Xpert MTB/RIF rollout from 65.9% (87/132) to 78.0% (494/633).

Conclusions

In Botswana, access to TB culture is challenging in remote populations; more accessible near-patient testing using Xpert MTB/RIF increased the number of patients receiving TB-specific testing on CSF and the number of confirmed TBM cases.

Tracking Cryptococcal Meningitis to Monitor HIV Program Success During the Treat All Era: An Analysis of National Data in Botswana

BACKGROUND

Cryptococcal meningitis (CM) causes substantial mortality in African countries with a high prevalence of human immunodeficiency virus (HIV), despite advances in disease management and increasing antiretroviral therapy (ART) coverage. Reliable diagnosis of CM is cheap and more accessible than other indicators of advanced HIV disease burden such as CD4 testing or investigation for disseminated tuberculosis; therefore, monitoring CM incidence has the potential to serve as a valuable metric of HIV programmatic success.

METHODS

Botswana national meningitis surveillance data from 2015 to 2022 were obtained from electronic health records. All electronic laboratory records from cerebrospinal fluid samples analyzed within government healthcare facilities in Botswana were extracted from a central online repository. Adjustments for missing data were made through triangulation with prospective cohort study datasets. CM case frequency was enumerated using a case definition and incidence calculated using national census data.

RESULTS

A total of 1744 episodes of CM were identified; incidence declined from 15.0 (95% confidence interval [CI], 13.4-16.7) cases/100 000 person-years in 2015 to 7.4 (95% CI, 6.4-8.6) cases/100 000 person-years in 2022. However, the rate of decline slowed following the introduction of universal treatment in 2016. The highest incidence was observed in men and individuals aged 40-44 years. The proportion of cases diagnosed through cryptococcal antigen testing increased from 35.5% to 86.3%.

CONCLUSIONS

CM incidence has decreased in Botswana following expansion of ART coverage but persists at a stubbornly high incidence. Most cases are now diagnosed through the cheap and easy-to-use cryptococcal antigen test, highlighting the potential of using CM as key metric of program success in the Treat All era.

The diagnosis of central nervous system infections in resource-limited settings and the use of novel and molecular diagnostic platforms to improve diagnosis

INTRODUCTION

Central nervous system infections (CNSI) disproportionately affect individuals in low-resource settings where diagnosis is challenging; large proportions of patients never receive a confirmed microbiological diagnosis resulting in inadequate management and high mortality. The epidemiology of CNSI varies globally and conventional diagnostics deployed in resource-limited settings have significant limitations, with an urgent need for improved diagnostic strategies.

AREAS COVERED

This review describes molecular platforms and other novel diagnostics used in the diagnosis of CNSI that are applicable to resource-limited settings. An extensive literature search of Medline and PubMed was performed. The emphasis is on investigations targeting infections of relevance to resource-limited settings either due to variation in regional CNSI epidemiology or due to increased prevalence in patients with immunosuppression. This includes commercially available multiplex PCR platforms, mycobacterial PCR platforms, and rapid diagnostics tests. To offer a framework for the optimal implementation in clinical settings, existing evidence highlighting the advantages and limitations of available platforms is reviewed.

EXPERT OPINION

The implementation of molecular platforms and other novel diagnostics has the potential to transform CNSI diagnosis in resource-limited settings, with several examples of successful rollout of novel diagnostics such as Xpert MTB/RIF Ultra and cryptococcal antigen testing.

Molecular point-of-care devices for the diagnosis of infectious diseases in resource-limited settings - A review of the current landscape, technical challenges, and clinical impact

Molecular point-of-care (POC) tests offer high sensitivity, rapid turnaround times, relative ease of use, and the convenience of laboratory-grade testing in the absence of formal laboratory spaces and equipment, making them appealing options for infectious disease diagnosis in resource-limited settings. In this review, we discuss the role and potential of molecular POC tests in resource-limited settings and their associated logistical challenges. We discuss U.S. Food and Drug Administration approval, Clinical Laboratory Improvement Amendments complexity levels, and the REASSURED criteria as a starting point for assessing options currently available inside and outside of the United States. We then present POC tests currently in research and development phases that have potential for commercialization and implementation in limited-resource settings. Finally, we review published studies that have assessed the clinical impact of molecular POC testing in limited- and moderate-resource settings.

Cryptococcal Meningitis in HIV-Negative Patients: A 12-Year Single-Center Experience in China

OBJECTIVE

Cryptococcal meningitis (CM) is a not rare condition in HIV-negative patients. Here, we describe the clinical characteristics, possible risk factors, and outcomes of HIV-negative patients with CM.

METHODS

Medical records from 99 HIV-negative patients with CM admitted to our hospital from 2010 to 2021 were reviewed systematically. We compared the clinical features and outcomes between patients with underlying diseases and otherwise healthy hosts.

RESULTS

The 99 HIV-negative CM patients had a mean age at presentation of 56.2 ± 16.2 years, and the female-to-male ratio was 77:22. A total of 52 (52.5%) CM patients had underlying conditions, and 47 patients (47.5%) had no underlying conditions. Kidney transplant represented the most frequent underlying condition (11.1%), followed by rheumatic disease (10.1%) and hematological diseases (9.1%). Compared to patients without underlying conditions, those with underlying conditions had significantly more fever, more steroid therapy, higher serum creatinine, and lower albumin, IgG, hemoglobin, and platelets (p < 0.05 for each). CM patients without underlying conditions had significantly more alcohol abuse than those with underlying conditions (31.9% vs. 9.6%, p = 0.011). By logistic regression analysis, male gender (OR = 3.16, p = 0.001), higher CSF WBC (OR = 2.88, p = 0.005), and protein (OR = 2.82, p = 0.002) were significantly associated with mortality.

CONCLUSION

Patients with underlying conditions had a similar mortality to patients without underlying conditions. Alcohol abuse was a probable risk factor for CM for previously healthy patients. Male gender, higher CSF WBC, and protein were significantly associated with mortality.

Laboratory Evaluation of the VISITECT Advanced Disease Semiquantitative Point-of-Care CD4 Test

BACKGROUND

Advanced HIV disease (AHD; CD4 counts <200 cells/µL) remains common in many low- and middle-income settings. An instrument-free point-of-care test to rapidly identify patients with AHD would facilitate implementation of the World Health Organization (WHO) recommended package of care. We performed a laboratory-based validation study to evaluate the performance of the VISITECT CD4 Advanced Disease assay in Botswana.

SETTING

A laboratory validation study.

METHODS

Venous blood samples from people living with HIV having baseline CD4 testing in Gaborone, Botswana, underwent routine testing using flow cytometry, followed by testing with the VISITECT CD4 Advanced Disease assay by a laboratory scientist blinded to the flow cytometry result with a visual read to determine whether the CD4 count was below 200 cells/µL. A second independent investigator conducted a visual read blinded to the results of flow cytometry and the initial visual read. The sensitivity and specificity of the VISITECT for detection of AHD were determined using flow cytometry as a reference standard, and interrater agreement in VISITECT visual reads assessed.

RESULTS

One thousand fifty-three samples were included in the analysis. The VISITECT test correctly identified 112/119 samples as having a CD4 count <200 cells/µL, giving a sensitivity of 94.1% (95% confidence interval: 88.3% to 97.6%) and specificity of 85.9% (95% confidence interval: 83.5% to 88.0%) compared with flow cytometry. Interrater agreement between the 2 independent readers was 97.5%, Kappa 0.92 ( P < 0.001).

CONCLUSIONS

The VISITECT CD4 advanced disease reliably identified individuals with low CD4 counts and could facilitate implementation of the WHO recommended package of interventions for AHD.

Invasive Fungal Diseases in Africa: A Critical Literature Review

Invasive fungal diseases (IFDs) are of huge concern in resource-limited settings, particularly in Africa, due to the unavailability of diagnostic armamentarium for IFDs, thus making definitive diagnosis challenging. IFDs have non-specific systemic manifestations overlapping with more frequent illnesses, such as tuberculosis, HIV, and HIV-related opportunistic infections and malignancies. Consequently, IFDs are often undiagnosed or misdiagnosed. We critically reviewed the available literature on IFDs in Africa to provide a better understanding of their epidemiology, disease burden to guide future research and interventions. Cryptococcosis is the most encountered IFD in Africa, accounting for most of the HIV-related deaths in sub-Saharan Africa. Invasive aspergillosis, though somewhat underdiagnosed and/or misdiagnosed as tuberculosis, is increasingly being reported with a similar predilection towards people living with HIV. More cases of histoplasmosis are also being reported with recent epidemiological studies, particularly from Western Africa, showing high prevalence rates amongst presumptive tuberculosis patients and patients living with HIV. The burden of pneumocystis pneumonia has reduced significantly probably due to increased uptake of anti-retroviral therapy among people living with HIV both in Africa, and globally. Mucormycosis, talaromycosis, emergomycosis, blastomycosis, and coccidiomycosis have also been reported but with very few studies from the literature. The emergence of resistance to most of the available antifungal drugs in Africa is yet of huge concern as reported in other regions. IFDs in Africa is much more common than it appears and contributes significantly to morbidity and mortality. Huge investment is needed to drive awareness and fungi related research especially in diagnostics and antifungal therapy.

Reversal of CSF HIV-1 Escape during Treatment of HIV-Associated Cryptococcal Meningitis in Botswana

Cerebrospinal fluid (CSF) viral escape has been poorly described among people with HIV-associated cryptococcal meningitis. We determined the prevalence of CSF viral escape and HIV-1 viral load (VL) trajectories in individuals treated for HIV-associated cryptococcal meningitis. A retrospective longitudinal study was performed using paired CSF and plasma collected prior to and during the antifungal treatment of 83 participants recruited at the Botswana site of the phase-3 AMBITION-cm trial (2018−2021). HIV-1 RNA levels were quantified then CSF viral escape (CSF HIV-1 RNA ≥ 0.5 log10 higher than plasma) and HIV-1 VL trajectories were assessed. CSF viral escape occurred in 20/62 (32.3%; 95% confidence interval [CI]: 21.9−44.6%), 13/52 (25.0%; 95% CI: 15.2−38.2%) and 1/33 (3.0%; 95% CI: 0.16−15.3%) participants at days 1, 7 and 14 respectively. CSF viral escape was significantly lower on day 14 compared to days 1 and 7, p = 0.003 and p = 0.02, respectively. HIV-1 VL decreased significantly from day 1 to day 14 post antifungal therapy in the CSF but not in the plasma (β = −0.47; 95% CI: −0.69 to −0.25; p < 0.001). CSF viral escape is high among individuals presenting with HIV-associated cryptococcal meningitis; however, antifungal therapy may reverse this, highlighting the importance of rapid initiation of antifungal therapy in these patients.

Human Herpesvirus-6 Detection in Cerebrospinal Fluid on the BioFire FilmArray Meningitis/Encephalitis Panel in a High HIV-prevalence African Setting

The prevalence and clinical relevance of human herpesvirus-6 (HHV-6) detection in cerebrospinal fluid (CSF) using multiplex polymerase chain reaction (PCR) testing in patients with suspected meningoencephalitis in high human immunodeficiency virus-prevalence African settings are not known. We describe the clinical and laboratory characteristics of 13 patients with HHV-6 CSF PCR positivity in Botswana.

Single-Dose Liposomal Amphotericin B Treatment for Cryptococcal Meningitis

BACKGROUND

Cryptococcal meningitis is a leading cause of human immunodeficiency virus (HIV)-related death in sub-Saharan Africa. Whether a treatment regimen that includes a single high dose of liposomal amphotericin B would be efficacious is not known.

METHODS

In this phase 3 randomized, controlled, noninferiority trial conducted in five African countries, we assigned HIV-positive adults with cryptococcal meningitis in a 1:1 ratio to receive either a single high dose of liposomal amphotericin B (10 mg per kilogram of body weight) on day 1 plus 14 days of flucytosine (100 mg per kilogram per day) and fluconazole (1200 mg per day) or the current World Health Organization-recommended treatment, which includes amphotericin B deoxycholate (1 mg per kilogram per day) plus flucytosine (100 mg per kilogram per day) for 7 days, followed by fluconazole (1200 mg per day) for 7 days (control). The primary end point was death from any cause at 10 weeks; the trial was powered to show noninferiority at a 10-percentage-point margin.

RESULTS

A total of 844 participants underwent randomization; 814 were included in the intention-to-treat population. At 10 weeks, deaths were reported in 101 participants (24.8%; 95% confidence interval [CI], 20.7 to 29.3) in the liposomal amphotericin B group and 117 (28.7%; 95% CI, 24.4 to 33.4) in the control group (difference, -3.9 percentage points); the upper boundary of the one-sided 95% confidence interval was 1.2 percentage points (within the noninferiority margin; P<0.001 for noninferiority). Fungal clearance from cerebrospinal fluid was -0.40 log10 colony-forming units (CFU) per milliliter per day in the liposomal amphotericin B group and -0.42 log10 CFU per milliliter per day in the control group. Fewer participants had grade 3 or 4 adverse events in the liposomal amphotericin B group than in the control group (50.0% vs. 62.3%).

CONCLUSIONS

Single-dose liposomal amphotericin B combined with flucytosine and fluconazole was noninferior to the WHO-recommended treatment for HIV-associated cryptococcal meningitis and was associated with fewer adverse events. (Funded by the European and Developing Countries Clinical Trials Partnership and others; Ambition ISRCTN number, ISRCTN72509687.).

Strategies for the diagnosis and management of meningitis in HIV-infected adults in resource limited settings

INTRODUCTION

The incidence of human immunodeficiency virus-1 (HIV-1) associated meningitis has been declining in the post-combination antiretroviral treatment (ART) era, although survival rates remain low for the common causes like tuberculosis and cryptococcal disease. Diagnosis and treatment of meningitis in HIV-1 is complicated by atypical clinical presentations, limited accuracy of diagnostic tests, access to diagnostic tests, and therapeutic agents in low- and middle-income countries (LMIC) and immune reconstitution inflammatory syndrome (IRIS).

AREAS COVERED

We provide an overview of the common etiologies of meningitis in HIV-1-infected adults, suggest a diagnostic approach based on readily available tests, and review specific chemotherapeutic agents, host-directed therapies, supportive care, timing of ART initiation, and considerations in the management of IRIS with a focus on resource-limited settings. They identify key knowledge gaps and suggest areas for future research.

EXPERT OPINION

Evidence-based management of HIV-1-associated meningitis is sparse for common etiologies. More readily available and sensitive diagnostic tests as well as standardized investigation strategies are required in LMIC. There is a lack of availability of recommended drugs in areas of high HIV-1 prevalence and a limited pipeline of novel chemotherapeutic agents. Host-directed therapies have been inadequately studied.

CNS infections in HIV

PURPOSE OF REVIEW

Central nervous system (CNS) infections associated with HIV remain significant contributors to morbidity and mortality, particularly among people living with HIV (PLWH) in resource-limited settings worldwide. In this review, we discuss several recent important scientific discoveries in the prevention, diagnosis, and management around two of the major causes of CNS opportunistic infections-tuberculous meningitis (TBM) and cryptococcal meningitis including immune reconstitution syndrome (IRIS) associated with cryptococcal meningitis. We also discuss the CNS as a possible viral reservoir, highlighting Cerebrospinal fluid viral escape.

RECENT FINDINGS

CNS infections in HIV-positive people in sub-Saharan Africa contribute to 15-25% of AIDS-related deaths. Morbidity and mortality in those is associated with delays in HIV diagnosis, lack of availability for antimicrobial treatment, and risk of CNS IRIS. The CNS may serve as a reservoir for replication, though it is unclear whether this can impact peripheral immunosuppression.

SUMMARY

Significant diagnostic and treatment advances for TBM and cryptococcal meningitis have yet to impact overall morbidity and mortality according to recent data. Lack of early diagnosis and treatment initiation, and also maintenance on combined antiretroviral treatment are the main drivers of the ongoing burden of CNS opportunistic infections. The CNS as a viral reservoir has major potential implications for HIV eradication strategies, and also control of CNS opportunistic infections.

The global burden of tuberculous meningitis in adults: A modelling study

Tuberculous meningitis (TBM) is the most lethal form of tuberculosis. The incidence and mortality of TBM is unknown due to diagnostic challenges and limited disaggregated reporting of treated TBM by existing surveillance systems. We aimed to estimate the incidence and mortality of TBM in adults (15+ years) globally. Using national surveillance data from Brazil, South Africa, the United Kingdom, the United States of America, and Vietnam, we estimated the fraction of reported tuberculosis that is TBM, and the case fatality ratios for treated TBM in each of these countries. We adjusted these estimates according to findings from a systematic review and meta-analysis and applied them to World Health Organization tuberculosis notifications and estimates to model the global TBM incidence and mortality. Assuming the case detection ratio (CDR) for TBM was the same as all TB, we estimated that in 2019, 164,000 (95% UI; 129,000-199,000) adults developed TBM globally; 23% were among people living with HIV. Almost 60% of incident TBM occurred in males and 20% were in adults 25-34 years old. 70% of global TBM incidence occurred in Southeast Asia and Africa. We estimated that 78,200 (95% UI; 52,300-104,000) adults died of TBM in 2019, representing 48% of incident TBM. TBM case fatality in those treated was on average 27%. Sensitivity analysis assuming improved detection of TBM compared to other forms of TB (CDR odds ratio of 2) reduced estimated global mortality to 54,900 (95% UI; 32,200-77,700); assuming instead worse detection for TBM (CDR odds ratio of 0.5) increased estimated mortality to 125,000 (95% UI; 88,800-161,000). Our results highlight the need for improved routine TBM monitoring, especially in high burden countries. Reducing TBM incidence and mortality will be necessary to achieve the End TB Strategy targets.

Spatio-temporal Distribution of Meningitis in HIV Patients in Northern Egypt (2000-2018)

BACKGROUND

Meningitis is a leading cause of death among patients living with HIV. There is no adequate tracking of the disease occurrence, distribution and etiologic agents among this risk group in Egypt, although the pattern could differ from that of the general population.

OBJECTIVES

We aimed to describe the spatio-temporal distribution of meningitis in HIV patients in a region of Northern Egypt over 18 years (2000-2018).

METHODS

We conducted a retrospective study of 352 adult HIV patients admitted to a tertiary care fever hospital with neurological manifestations suggesting meningitis. We retrieved from inpatient records all data relevant to patient demographics, clinical presentation, diagnostic work-up, results of laboratory investigations (CSF, blood, imaging), definitive diagnosis, and in-hospital mortality.

RESULTS

The overall trend of over 2 decades showed fluctuating incidence of meningitis in HIV infected patients and increasing spread into rural areas, with a uniform circulation among adult males. Cryptococcal meningitis was the most common etiologic agent (26.9%) and was associated with worse outcomes. Focal neurological deficit (38.5%), cranial nerve involvement (48.1%) were common features in TB Meningitis. The mortality was high (56.8%) and was significantly associated with low CD4+ count, advanced AIDs clinical stage and the presence of co-morbidities.

CONCLUSION

Despite the availability of cART, meningitis, particularly cryptococcal, is common in HIV/AIDS population in Egypt. Continued efforts are desperately needed to improve the outcomes of HIV-infected patients.

Optimizing Laboratory Diagnostic Services for Infectious Meningitis in the Meningitis Belt of sub-Saharan Africa

For longer than a century, the "meningitis belt" of sub-Saharan Africa has experienced the largest-ever global meningitis epidemic. Whereas HIV-associated immunosuppression drives higher susceptibility to environmental infectious organisms with tropism for the central nervous system (CNS), most diagnostic laboratories in the belt stick to N. meningitidis, H. influenzae, and S. pneumoniae. Cryptococcus neoformans has been the leading cause of death (incidence, 89%; death, 75%). To establish whether diagnostic services target geographically important pathogens, there is a need to know the current spectrum of etiology. Given Africa's agro-silvo-pastoralism, the One Health diagnostic approach is recommended. Considering  multipathogen detection capacity, needed speed for corticosteroid therapy decision, and susceptibility/resistance to antimicrobials with improved CNS penetration, proposed laboratory categorization will help neurologists to choose suitable services.