Cellular immune response to SARS-CoV-2 and clinical presentation in individuals exposed to endemic malaria.

Ghana and other parts of West Africa have experienced lower COVID-19 mortality rates than other regions. This phenomenon has been hypothesized to be associated with previous exposure to infections such as malaria. This study investigated the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the influence of previous malaria exposure. Blood samples were collected from individuals with asymptomatic or symptomatic COVID-19 (n = 217). A variety of assays were used to characterize the SARS-CoV-2-specific immune response, and malaria exposure was quantified using Plasmodium falciparum ELISA. The study found evidence of attenuated immune responses to COVID-19 among asymptomatic individuals, with elevated proportions of non-classical monocytes and greater memory B cell activation. Symptomatic patients displayed higher P. falciparum-specific T cell recall immune responses, whereas asymptomatic individuals demonstrated elevated P. falciparum antibody levels. Summarily, this study suggests that P. falciparum exposure-associated immune modulation may contribute to reduced severity of SARS-CoV-2 infection among people living in malaria-endemic regions.

Development and utility of a SARS-CoV-2 pseudovirus assay for compound screening and antibody neutralization assays.

Background: The highly infectious nature of SARS-CoV-2 necessitates using bio-containment facilities to study viral pathogenesis and identify potent antivirals. However, the lack of high-level bio-containment laboratories across the world has limited research efforts into SARS-CoV-2 pathogenesis and the discovery of drug candidates. Previous research has reported that non-replicating SARS-CoV-2 Spike-pseudotyped viral particles are effective tools to screen for and identify entry inhibitors and neutralizing antibodies. Methods: To generate SARS-CoV-2 pseudovirus, a lentiviral packaging plasmid p8.91, a luciferase expression plasmid pCSFLW, and SARS-CoV-2 Spike expression plasmids (Wild-type (D614G) or Delta strain) were co-transfected into HEK293 cells to produce a luciferase-expressing non-replicating pseudovirus which expresses SARS-CoV-2 spike protein on the surface. For relative quantitation, HEK293 cells expressing ACE2 (ACE2-HEK293) were infected with the pseudovirus, after which luciferase activity in the cells was measured as a relative luminescence unit. The ACE2-HEK293/Pseudovirus infection system was used to assess the antiviral effects of some compounds and plasma from COVID-19 patients to demonstrate the utility of this assay for drug discovery and neutralizing antibody screening. Results: We successfully produced lentiviral-based SARS-CoV2 pseudoviruses and ACE2-expressing HEK293 cells. The system was used to screen compounds for SARS-CoV-2 entry inhibitors and identified two compounds with potent activity against SARS-CoV-2 pseudovirus entry into cells. The assay was also employed to screen patient plasma for neutralizing antibodies against SARS-CoV-2, as a precursor to live virus screening, using successful hits. Significance: This assay is scalable and can perform medium-to high-throughput screening of antiviral compounds with neither severe biohazard risks nor the need for higher-level containment facilities. Now fully deployed in our resource-limited laboratory, this system can be applied to other highly infectious viruses by swapping out the envelope proteins in the plasmids used in pseudovirus production.

The COVID-19, tuberculosis and HIV/AIDS: Ménage à Trois.

In December 2019, a novel pneumonic condition, Coronavirus disease 2019 (COVID- 19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), broke out in China and spread globally. The presentation of COVID-19 is more severe in persons with underlying medical conditions such as Tuberculosis (TB), Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS) and other pneumonic conditions. All three diseases are of global concern and can significantly affect the lungs with characteristic cytokine storm, immunosuppression, and respiratory failure. Co-infections of SARS-CoV-2 with HIV and Mycobacterium tuberculosis (Mtb) have been reported, which may influence their pathogenesis and disease progression. Pulmonary TB and HIV/AIDS patients could be more susceptible to SARS-CoV-2 infection leading to lethal synergy and disease severity. Therefore, the biological and epidemiological interactions of COVID-19, HIV/AIDS, and TB need to be understood holistically. While data is needed to predict the impact of the COVID-19 pandemic on these existing diseases, it is necessary to review the implications of the evolving COVID-19 management on HIV/AIDS and TB control, including therapy and funding. Also, the impact of long COVID on patients, who may have this co-infection. Thus, this review highlights the implications of COVID-19, HIV/AIDS, and TB co-infection compares disease mechanisms, addresses growing concerns, and suggests a direction for improved diagnosis and general management.

Human Norovirus Triggers Primary B Cell Immune Activation In Vitro.

Human norovirus (HNoV) is a global health and socioeconomic burden, estimated to infect every individual at least five times during their lifetime. The underlying mechanism for the potential lack of long-term immune protection from HNoV infections is not understood and prompted us to investigate HNoV susceptibility of primary human B cells and its functional impact. Primary B cells isolated from whole blood were infected with HNoV-positive stool samples and harvested at 3 days postinfection (dpi) to assess the viral RNA yield by reverse transcriptase quantitative PCR (RT-qPCR). A 3- to 18-fold increase in the HNoV RNA yield was observed in 50 to 60% of donors. Infection was further confirmed in B cells derived from splenic and lymph node biopsy specimens. Next, we characterized infection of whole-blood-derived B cells by flow cytometry in specific functional B cell subsets (naive CD27- IgD+, memory-switched CD27+ IgD-, memory-unswitched CD27+ IgD+, and double-negative CD27- IgD- cells). While the susceptibilities of the subsets were similar, changes in the B cell subset distribution upon infection were observed, which were also noted after treatment with HNoV virus-like particles and the predicted recombinant NS1 protein. Importantly, primary B cell stimulation with the predicted recombinant NS1 protein triggered B cell activation and induced metabolic changes. These data demonstrate that primary B cells are susceptible to HNoV infection and suggest that the NS1 protein can alter B cell activation and metabolism in vitro, which could have implications for viral pathogenesis and immune responses in vivo. IMPORTANCE Human norovirus (HNoV) is the most prevalent causative agent of gastroenteritis worldwide. Infection results in a self-limiting disease that can become chronic and severe in the immunocompromised, the elderly, and infants. There are currently no approved therapeutic and preventative strategies to limit the health and socioeconomic burdens associated with HNoV infections. Moreover, HNoV does not elicit lifelong immunity as repeat infections are common, presenting a challenge for vaccine development. Given the importance of B cells for humoral immunity, we investigated the susceptibility and impact of HNoV infection on human B cells. We found that HNoV replicates in human primary B cells derived from blood, spleen, and lymph node specimens, while the nonstructural protein NS1 can activate B cells. Because of the secreted nature of NS1, we put forward the hypothesis that HNoV infection can modulate bystander B cell function with potential impacts on systemic immune responses.

Preliminary Investigation into Plasmodium-like Piroplasms (Babesia/Theileria) among Cattle, Dogs and Humans in A Malaria-Endemic, Resource-Limited Sub-Saharan African City.

Babesia and Theileria are protozoan parasites belonging to the order piroplasmida, transmitted by hard ticks, and can cause diseases known as piroplasmosis. Human infections are usually asymptomatic, except in immuno-compromised persons who present malaria-like symptoms. Moreover, microscopically, the morphologies of Babesia and Theileria can resemble that of the malaria parasite, Plasmodium. In malaria-endemic areas with limited resources, these similarities can increase the possibility of misdiagnosing a patient as having malaria instead of piroplasmosis, which may further lead to inappropriate choice of disease management. This preliminary investigation aimed at detecting Babesia/Theileria in cattle, dogs and humans in some parts of Accra. Whole blood samples were taken from febrile cattle (n = 30) and dogs (n = 33), as well as humans diagnosed with malaria (n = 150). Blood samples of all study subjects were microscopically screened for possible presence of haemoparasites. Samples whose smears had features suggestive of possible piroplasmic infection were all given the label "suspected Babesia/Theileria-infected" samples. Nested polymerase chain reaction (PCR) was performed on extracted deoxyribonucelic acid (DNA) from all the "suspected" samples of cattle, dogs and humans, with primer sets that can detect 18S rRNA genes of Babesia/Theileria spp. In addition to this, amplification was performed on the "suspected" dog samples using the BcW-A/BcW-B primer set which detects the 18S rRNA genes of B. canis, while the BoF/BoR primer set which targets the rap-1 region of B. bovis and another primer set which detects the 18S rRNA genes of most bovine Babesia spp. (including B. divergens) were used on the suspected cattle samples. For the human samples, however, additional amplification was done on the extracted DNA using primers for the three other Babesia targeted (B. divergens, B. bovis and B. canis). Microscopy showed possible Babesia/Theileria infection suspected in all three groups of subjects in the following proportions: cattle (10/30; 33%), dogs (3/33; 9%) and humans (6/150; 4%). DNA from one-third of the "suspected" dog samples yielded amplification with Babesia canis primers. Moreover, a broad-detecting set of primers (that can amplify some Babesia and Theileria species) amplified DNA from nine (9/30; 30%) of the "suspected" cattle samples, but none from those of the humans. Although for this study conducted in the city, the Babesia/Theileria primers used did not amplify DNA from the six "suspected" human samples; the possibility of Babesia/Theileria infection in humans in other parts of the country cannot be overruled. There is therefore a need for further studies on possible emergence of human babesiosis/theileriosis in other parts of Ghana and sequencing for specific identification of any circulating strain.

Macrophage inflammatory state influences susceptibility to lysosomal damage.

Macrophages possess mechanisms for reinforcing the integrity of their endolysosomes against damage. This property, termed inducible renitence, was previously observed in murine macrophages stimulated with LPS, peptidoglycan, IFNγ, or TNFα, which suggested roles for renitence in macrophage resistance to infection by membrane-damaging pathogens. This study analyzed additional inducers of macrophage differentiation for their ability to increase resistance to lysosomal damage by membrane-damaging particles. Renitence was evident in macrophages activated with LPS plus IFNγ, PGE2 , or adenosine, and in macrophages stimulated with IFN-ß, but not in macrophages activated with IL-4 or IL-10. These responses indicated roles for macrophage subtypes specialized in host defense and suppression of immune responses, but not those involved in wound healing. Consistent with this pattern, renitence could be induced by stimulation with agonists for TLR, which required the signaling adaptors MyD88 and/or TRIF, and by infection with murine norovirus-1. Renitence induced by LPS was dependent on cytokine secretion by macrophages. However, no single secreted factor could explain all the induced responses. Renitence induced by the TLR3 agonist Poly(I:C) was mediated in part by the type I IFN response, but renitence induced by Pam3CSK4 (TLR2/1), LPS (TLR4), IFNγ, or TNFα was independent of type 1 IFN signaling. Thus, multiple pathways for inducing macrophage resistance to membrane damage exist and depend on the particular microbial stimulus sensed.

Akt Plays Differential Roles during the Life Cycles of Acute and Persistent Murine Norovirus Strains in Macrophages.

Akt (protein kinase B) is a key signaling protein in eukaryotic cells that controls many cellular processes, such as glucose metabolism and cell proliferation, for survival. As obligate intracellular pathogens, viruses modulate host cellular processes, including Akt signaling, for optimal replication. The mechanisms by which viruses modulate Akt and the resulting effects on the infectious cycle differ widely depending on the virus. In this study, we explored the effect of Akt serine 473 phosphorylation (p-Akt) during murine norovirus (MNV) infection. p-Akt increased during infection of murine macrophages with acute MNV-1 and persistent CR3 and CR6 strains. Inhibition of Akt with MK2206, an inhibitor of all three isoforms of Akt (Akt1/2/3), reduced infectious virus progeny of all three virus strains. This reduction was due to decreased viral genome replication (CR3), defective virus assembly (MNV-1), or altered cellular egress (CR3 and CR6) in a virus strain-dependent manner. Collectively, our data demonstrate that Akt activation increases in macrophages during the later stages of the MNV infectious cycle, which may enhance viral infection in unique ways for different virus strains. The data, for the first time, indicate a role for Akt signaling in viral assembly and highlight additional phenotypic differences between closely related MNV strains. IMPORTANCE Human noroviruses (HNoV) are a leading cause of viral gastroenteritis, resulting in high annual economic burden and morbidity, yet there are no small-animal models supporting productive HNoV infection or robust culture systems producing cell culture-derived virus stocks. As a result, research on drug discovery and vaccine development against norovirus infection has been challenging, and no targeted antivirals or vaccines against HNoV are approved. On the other hand, murine norovirus (MNV) replicates to high titers in cell culture and is a convenient and widespread model in norovirus research. Our data demonstrate the importance of Akt signaling during the late stage of the MNV life cycle. Notably, the effect of Akt signaling on genome replication, virus assembly, and cellular egress is virus strain specific, highlighting the diversity of biological phenotypes despite small genetic variability among norovirus strains. This study is the first to demonstrate a role for Akt in viral assembly.

SARS-CoV-2 disease severity and transmission efficiency is increased for airborne compared to fomite exposure in Syrian hamsters.

Transmission of SARS-CoV-2 is driven by contact, fomite, and airborne transmission. The relative contribution of different transmission routes remains subject to debate. Here, we show Syrian hamsters are susceptible to SARS-CoV-2 infection through intranasal, aerosol and fomite exposure. Different routes of exposure present with distinct disease manifestations. Intranasal and aerosol inoculation causes severe respiratory pathology, higher virus loads and increased weight loss. In contrast, fomite exposure leads to milder disease manifestation characterized by an anti-inflammatory immune state and delayed shedding pattern. Whereas the overall magnitude of respiratory virus shedding is not linked to disease severity, the onset of shedding is. Early shedding is linked to an increase in disease severity. Airborne transmission is more efficient than fomite transmission and dependent on the direction of the airflow. Carefully characterized SARS-CoV-2 transmission models will be crucial to assess potential changes in transmission and pathogenic potential in the light of the ongoing SARS-CoV-2 evolution.

Egress of non-enveloped enteric RNA viruses.

A long-standing paradigm in virology was that non-enveloped viruses induce cell lysis to release progeny virions. However, emerging evidence indicates that some non-enveloped viruses exit cells without inducing cell lysis, while others engage both lytic and non-lytic egress mechanisms. Enteric viruses are transmitted via the faecal-oral route and are important causes of a wide range of human infections, both gastrointestinal and extra-intestinal. Virus cellular egress, when fully understood, may be a relevant target for antiviral therapies, which could minimize the public health impact of these infections. In this review, we outline lytic and non-lytic cell egress mechanisms of non-enveloped enteric RNA viruses belonging to five families: Picornaviridae, Reoviridae, Caliciviridae, Astroviridae and Hepeviridae. We discuss factors that contribute to egress mechanisms and the relevance of these mechanisms to virion stability, infectivity and transmission. Since most data were obtained in traditional two-dimensional cell cultures, we will further attempt to place them into the context of polarized cultures and in vivo pathogenesis. Throughout the review, we highlight numerous knowledge gaps to stimulate future research into the egress mechanisms of these highly prevalent but largely understudied viruses.

K18-hACE2 mice develop respiratory disease resembling severe COVID-19.

SARS-CoV-2 emerged in late 2019 and resulted in the ongoing COVID-19 pandemic. Several animal models have been rapidly developed that recapitulate the asymptomatic to moderate disease spectrum. Now, there is a direct need for additional small animal models to study the pathogenesis of severe COVID-19 and for fast-tracked medical countermeasure development. Here, we show that transgenic mice expressing the human SARS-CoV-2 receptor (angiotensin-converting enzyme 2 [hACE2]) under a cytokeratin 18 promoter (K18) are susceptible to SARS-CoV-2 and that infection resulted in a dose-dependent lethal disease course. After inoculation with either 104 TCID50 or 105 TCID50, the SARS-CoV-2 infection resulted in rapid weight loss in both groups and uniform lethality in the 105 TCID50 group. High levels of viral RNA shedding were observed from the upper and lower respiratory tract and intermittent shedding was observed from the intestinal tract. Inoculation with SARS-CoV-2 resulted in upper and lower respiratory tract infection with high infectious virus titers in nasal turbinates, trachea and lungs. The observed interstitial pneumonia and pulmonary pathology, with SARS-CoV-2 replication evident in pneumocytes, were similar to that reported in severe cases of COVID-19. SARS-CoV-2 infection resulted in macrophage and lymphocyte infiltration in the lungs and upregulation of Th1 and proinflammatory cytokines/chemokines. Extrapulmonary replication of SARS-CoV-2 was observed in the cerebral cortex and hippocampus of several animals at 7 DPI but not at 3 DPI. The rapid inflammatory response and observed pathology bears resemblance to COVID-19. Additionally, we demonstrate that a mild disease course can be simulated by low dose infection with 102 TCID50 SARS-CoV-2, resulting in minimal clinical manifestation and near uniform survival. Taken together, these data support future application of this model to studies of pathogenesis and medical countermeasure development.

K18-hACE2 mice develop respiratory disease resembling severe COVID-19.

SARS-CoV-2 emerged in late 2019 and resulted in the ongoing COVID-19 pandemic. Several animal models have been rapidly developed that recapitulate the asymptomatic to moderate disease spectrum. Now, there is a direct need for additional small animal models to study the pathogenesis of severe COVID-19 and for fast-tracked medical countermeasure development. Here, we show that transgenic mice expressing the human SARS-CoV-2 receptor (angiotensin-converting enzyme 2 [hACE2]) under a cytokeratin 18 promoter (K18) are susceptible to SARS-CoV-2 and that infection resulted in a dose-dependent lethal disease course. After inoculation with either 10 4 TCID 50 or 10 5 TCID 50 , the SARS-CoV-2 infection resulted in rapid weight loss in both groups and uniform lethality in the 10 5 TCID 50 group. High levels of viral RNA shedding were observed from the upper and lower respiratory tract and intermittent shedding was observed from the intestinal tract. Inoculation with SARS-CoV-2 resulted in upper and lower respiratory tract infection with high infectious virus titers in nasal turbinates, trachea and lungs. The observed interstitial pneumonia and pulmonary pathology, with SARS-CoV-2 replication evident in pneumocytes, were similar to that reported in severe cases of COVID-19. SARS-CoV-2 infection resulted in macrophage and lymphocyte infiltration in the lungs and upregulation of Th1 and proinflammatory cytokines/chemokines. Extrapulmonary replication of SARS-CoV-2 was observed in the cerebral cortex and hippocampus of several animals at 7 DPI but not at 3 DPI. The rapid inflammatory response and observed pathology bears resemblance to COVID-19. Taken together, this suggests that this mouse model can be useful for studies of pathogenesis and medical countermeasure development. AUTHORS SUMMARY: The disease manifestation of COVID-19 in humans range from asymptomatic to severe. While several mild to moderate disease models have been developed, there is still a need for animal models that recapitulate the severe and fatal progression observed in a subset of patients. Here, we show that humanized transgenic mice developed dose-dependent disease when inoculated with SARS-CoV-2, the etiological agent of COVID-19. The mice developed upper and lower respiratory tract infection, with virus replication also in the brain after day 3 post inoculation. The pathological and immunological diseases manifestation observed in these mice bears resemblance to human COVID-19, suggesting increased usefulness of this model for elucidating COVID-19 pathogenesis further and testing of countermeasures, both of which are urgently needed.

Intestinal Enteroid Culture for Human Astroviruses.

Human astroviruses (HAstV) are non-enveloped, positive-sense single stranded RNA viruses that typically cause gastroenteritis in children, the elderly and among immunocompromised individuals. Some HAstV species have also been implicated in neurological diseases. It is important to study these viruses to understand the pathogenesis and develop therapeutics. Here we describe HAstV infection in epithelium-only human intestinal enteroids (HIE) isolated from biopsy-derived intestinal crypts. Although different HAstV clades have been propagated in transformed immortalized cell lines such as A549, Caco-2, HEK293T and Huh7.5, we chose HIE because they better mimic the human intestine and thus are more physiologically relevant. Additionally, HIE support the replication of all HAstV clades including clinical samples, thus making HIE a valuable potential universal model to study HAstV biology.

SARS-CoV-2 disease severity and transmission efficiency is increased for airborne but not fomite exposure in Syrian hamsters.

Transmission of SARS-CoV-2 is driven by contact, fomite, and airborne transmission. The relative contribution of different transmission routes remains subject to debate. Here, we show Syrian hamsters are susceptible to SARS-CoV-2 infection through intranasal, aerosol and fomite exposure. Different routes of exposure presented with distinct disease manifestations. Intranasal and aerosol inoculation caused more severe respiratory pathology, higher virus loads and increased weight loss. Fomite exposure led to milder disease manifestation characterized by an anti-inflammatory immune state and delayed shedding pattern. Whereas the overall magnitude of respiratory virus shedding was not linked to disease severity, the onset of shedding was. Early shedding was linked to an increase in disease severity. Airborne transmission was more efficient than fomite transmission and dependent on the direction of the airflow. Carefully characterized of SARS-CoV-2 transmission models will be crucial to assess potential changes in transmission and pathogenic potential in the light of the ongoing SARS-CoV-2 evolution.

Cytological and Wet Mount Microscopic Observations Made in Urine of Schistosoma haematobium-Infected Children: Hint of the Implication in Bladder Cancer.

BACKGROUND: Schistosomiasis is the second major human parasitic disease next to malaria, in terms of socioeconomic and public health consequences, especially in sub-Saharan Africa. Schistosoma haematobium (S. haematobium) is a trematode and one of the species of Schistosoma that cause urogenital schistosomiasis (urinary schistosomiasis). Although the knowledge of this disease has improved over the years, there are still endemic areas, with most of the reported cases in Africa, including Ghana. Not much has been done in Ghana to investigate cytological abnormalities in individuals within endemic communities, although there are epidemiologic evidences linking S. haematobium infection with carcinoma of the bladder. AIM: The aim of this study was to identify microscopic and cytological abnormalities in the urine deposits of S. haematobium-infected children. METHODOLOGY: Three hundred and sixty-seven (367) urine samples were collected from school children in Zenu and Weija communities. All the samples were examined microscopically for the presence of S. haematobium eggs, after which the infected samples and controls were processed for cytological investigation. RESULTS: S. haematobium ova were present in 66 (18.0%) out of the 367 urine samples. Inflammatory cells (82%, 54/66), hyperkeratosis (47%, 31/66), and squamous cell metaplasia (24%, 16/66) were the main observations made during the cytological examination of the S. haematobium-infected urine samples. CONCLUSION: Cytological abnormalities in S. haematobium-infected children may play an important role in the severity of the disease, leading to the possible development of bladder cancer in later years, if early attention is not given. Therefore, routine cytological screening for urogenital schistosomiasis patients (especially children) at hospitals in S. haematobium-endemic locations is recommended.

Elimination of lymphatic filariasis: current perspectives on mass drug administration.

Following the London declaration on neglected tropical diseases (NTDs) in 2012 and inspired by the WHO 2020 roadmap to control or eliminate NTDs, the Global Programme to Eliminate Lymphatic Filariasis (GPELF) intensified preventive chemotherapy and management of morbidity as the two main strategies to enhance progress towards the elimination of lymphatic filariasis (LF). This paper focuses on current perspectives of mass drug administration (MDA) towards the elimination of LF. The goal of MDA is to reduce the density of parasites circulating in the blood of infected persons and the intensity of infection in communities to levels where transmission is no longer sustainable by the mosquito vector. Three drugs, diethylcarbamazine, albendazole, and ivermectin are currently available for LF treatment, and their effectiveness and relative safety have opened the possibility of treating the entire population at risk. Currently, almost all LF endemic countries rely on the single-dose two-drug regimen recommended by the GPELF to achieve elimination. The 4th WHO report on NTDs has indicated that considerable progress has been made towards elimination of LF in some countries while acknowledging some challenges. In this review, we conclude that the 2020 elimination goal can be achieved if issues pertaining to the drug distribution, health system and implementation challenges are addressed.

An evaluation of Wb123 antibody elisa in individuals treated with ivermectin and albendazole, and implementation challenges in Africa.

The development of antibody testing for the diagnosis of lymphatic filariasis (LF) is intended to enhance the monitoring and evaluation activities of the Global Program for the Elimination of LF. This is due to the fact that antibody tests are expected to be the most sensitive at detecting exposure to LF compared to antigen that takes longer to develop. To this end a new antibody-based enzyme linked immunosorbent assay (ELISA) to Wuchereria bancrofti antigen Wb123 has been developed and further designed into a point of care rapid diagnostic test, under evaluation. In pre-treatment surveys, individuals were tested for antigen using the immuno-chromatographic test (ICT) card, and night blood microfilariae, after which all positives were treated using Ivermectin and Albendazole. The Wb123 ELISA was tested in antigen positive individuals, three months after they were treated. Samples were also tested for ICT and night blood microfilariae. The results revealed a reduction in microfilariae and ICT prevalence after treatment. Antigen and antibody prevalence increased with age. However, there was no correlation with the antibody responses observed. The mean WB123 antibody titers were higher among ICT positives, but not significantly different from ICT negative persons. While the Wb123 is targeted for use in untreated populations, further evaluations and guidelines will be required to define its use in populations that have undergone treatment for the control of LF.

Evaluation of human and mosquito based diagnostic tools for defining endpoints for elimination of Anopheles transmitted lymphatic filariasis in Ghana.

BACKGROUND: The decision to stop mass drug administration (MDA) and monitor recrudescence has to be made when endpoints for elimination of lymphatic filariasis (LF) have been achieved. Highly sensitive and specific diagnostic tools are required to do this. The main objective of this study was to determine most effective diagnostic tools for assessing interruption of LF transmission. METHODS: The presence of filarial infection in blood and mosquito samples was determined using five diagnostic tools: Brugia malayi-14 (BM14) antibody detection ELISA, Onchocerca gibsoni antigen (Og4C3) based ELISA, PCR, immunochromatography (ICT) card test and blood smear. The study was carried out in two communities in the Central Region of Ghana. RESULTS: OG4C3 was found to be the most sensitive test but ICT, the second most sensitive, was the most field applicable. PCR was found to be the most specific. Thirteen out of 30 pools of anopheles mosquitoes tested positive for the DNA of Wuchereria bancrofti. CONCLUSIONS: Very low antigen prevalence in primary school children indicates that MDA is working, so children born since the intervention was put in place are not getting infected. Inclusion of xenomonitoring in monitoring the effectiveness of MDA will give a better indication as to when transmission has been interrupted especially in areas where microfilaria prevalence is lower than 1%.

Transmission assessment surveys (TAS) to define endpoints for lymphatic filariasis mass drug administration: a multicenter evaluation.

BACKGROUND: Lymphatic filariasis (LF) is targeted for global elimination through treatment of entire at-risk populations with repeated annual mass drug administration (MDA). Essential for program success is defining and confirming the appropriate endpoint for MDA when transmission is presumed to have reached a level low enough that it cannot be sustained even in the absence of drug intervention. Guidelines advanced by WHO call for a transmission assessment survey (TAS) to determine if MDA can be stopped within an LF evaluation unit (EU) after at least five effective rounds of annual treatment. To test the value and practicality of these guidelines, a multicenter operational research trial was undertaken in 11 countries covering various geographic and epidemiological settings. METHODOLOGY: The TAS was conducted twice in each EU with TAS-1 and TAS-2 approximately 24 months apart. Lot quality assurance sampling (LQAS) formed the basis of the TAS survey design but specific EU characteristics defined the survey site (school or community), eligible population (6-7 year olds or 1(st)-2(nd) graders), survey type (systematic or cluster-sampling), target sample size, and critical cutoff (a statistically powered threshold below which transmission is expected to be no longer sustainable). The primary diagnostic tools were the immunochromatographic (ICT) test for W. bancrofti EUs and the BmR1 test (Brugia Rapid or PanLF) for Brugia spp. EUs. PRINCIPAL FINDINGS/CONCLUSIONS: In 10 of 11 EUs, the number of TAS-1 positive cases was below the critical cutoff, indicating that MDA could be stopped. The same results were found in the follow-up TAS-2, therefore, confirming the previous decision outcome. Sample sizes were highly sex and age-representative and closely matched the target value after factoring in estimates of non-participation. The TAS was determined to be a practical and effective evaluation tool for stopping MDA although its validity for longer-term post-MDA surveillance requires further investigation.