Anja De Weggheleire

Bio: Anja De Weggheleire is an academic researcher from Institute of Tropical Medicine Antwerp. The author has contributed to research in topics: Hepatitis C & Ebola virus. The author has an hindex of 9, co-authored 29 publications receiving 372 citations.

Prozone in malaria rapid diagnostics tests: how many cases are missed?

Abstract: Prozone means false-negative or false-low results in antigen-antibody reactions, due to an excess of either antigen or antibody. The present study prospectively assessed its frequency for malaria rapid diagnostic tests (RDTs) and Plasmodium falciparum samples in an endemic field setting. From January to April 2010, blood samples with P. falciparum high parasitaemia (≥ 4% red blood cells infected) were obtained from patients presenting at the Provincial Hospital of Tete (Mozambique). Samples were tested undiluted and 10-fold diluted in saline with a panel of RDTs and results were scored for line intensity (no line visible, faint, weak, medium and strong). Prozone was defined as a sample which showed no visible test line or a faint or weak test line when tested undiluted, and a visible test line of higher intensity when tested 10-fold diluted, as observed by two blinded observers and upon duplicate testing. A total of 873/7,543 (11.6%) samples showed P. falciparum, 92 (10.5%) had high parasitaemia and 76 were available for prozone testing. None of the two Pf-pLDH RDTs, but all six HRP-2 RDTs showed prozone, at frequencies between 6.7% and 38.2%. Negative and faint HRP-2 lines accounted for four (3.8%) and 15 (14.4%) of the 104 prozone results in two RDT brands. For the most affected brand, the proportions of prozone with no visible or faint HRP-2 lines were 10.9% (CI: 5.34-19.08), 1.2% (CI: 0.55-2.10) and 0.1% (CI: 0.06-0.24) among samples with high parasitaemia, all positive samples and all submitted samples respectively. Prozone occurred mainly, but not exclusively, among young children. Prozone occurs at different frequency and intensity in HRP-2 RDTs and may decrease diagnostic accuracy in the most affected RDTs.

Seroprevalence of transfusion-transmissible infections and evaluation of the pre-donation screening performance at the Provincial Hospital of Tete, Mozambique

Abstract: The World Health Organization recommends universal and quality-controlled screening of blood donations for the major transfusion-transmissible infections (TTIs): human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV) and syphilis. The study objectives were to determine the seroprevalence of these TTIs among blood donors at the Provincial Hospital of Tete, Mozambique, and to assess the local pre-donation screening performance. All consenting voluntary and replacement candidate blood donors were consecutively included from February to May 2009. Sera of all candidates, independent of deferral by questionnaire, were submitted to screening with quality-assured rapid or simple assays for HIV, HBV surface antigen (HBsAg), HCV and syphilis. Assays locally used by the blood bank for HBV and syphilis screening were run in parallel to quality-assured external assays supplied during the study, and all discordant samples were submitted to confirmation testing in reference laboratories in Mozambique and Belgium. Of 750 consenting candidates (50.5% of voluntary donors), 71 (9.5%) were deferred by the questionnaire, including 38 specifically because of risk behavior for TTI. Of the 679 non-deferred candidates, 127 (18.7%) had serological confirmation of at least one TTI, with a lower prevalence in voluntary than in replacement donors (15.2% versus 22.4%, p = 0.016). Seroprevalence of HIV, HBsAg and syphilis infections was 8.5%, 10.6 % and 1.2%. No confirmed HCV infection was found. Seroprevalence of TTIs was similar in the 38 candidates deferred for TTI risk as in the non-deferred group, except for HBsAg (26.3 % versus 10.6 %; p = 0.005). The local assays used for HBV and syphilis had sensitivities of 98.4% and 100% and specificities of 80.4% and 98.8% respectively. This resulted in the rejection of 110 of the 679 blood donations (16.2%) because of false positive results. The seroprevalence of TTIs after questionnaire screening is high in Tete, Mozambique, but HCV infection does not appear as a major issue. The questionnaire did not exclude effectively HIV-infected donor candidates, while the locally used assays led to unnecessary rejection of many safe donations. A contextualized questionnaire and consistent use of quality-assured assays would considerably improve the current screening procedure for blood donation.

Hepatitis B and C co-infection among HIV-infected adults while on antiretroviral treatment: long-term survival, CD4 cell count recovery and antiretroviral toxicity in Cambodia.

Abstract: Background Despite the high burden, there is a dearth of (long-term) outcome data of hepatitis B virus (HBV) and hepatitis C virus (HCV) co-infected patients receiving antiretroviral treatment (ART) in a clinical setting in resource-constrained settings, particularly from Asia. Methods We conducted a retrospective cohort study including all adults initiating standard ART (non-tenofovir-based) between 03/2003 and 09/2012. HBV infection was diagnosed by HBV surface antigen detection. HCV diagnosis relied on antibody detection. The independent effect of HBV and HCV on long-term (≥5 years) ART response in terms of mortality (using Cox regression), severe livertoxicity (using logistic regression) and CD4 count increase (using mixed-effects modelling) was determined. Results A total of 3089 adults were included (median age: 35 years (interquartile range 30–41); 46% male), of whom 341 (11.0%) were co-infected with HBV and 163 (5.3%) with HCV. Over a median ART follow-up time of 4.3 years, 240 individuals died. Mortality was 1.6 higher for HBV co-infection in adjusted analysis (P = 0.010). After the first year of ART, the independent mortality risk was 3-fold increased in HCV co-infection (P = 0.002). A total of 180 (5.8%) individuals discontinued efavirenz or nevirapine due to severe livertoxicity, with an independently increased risk for HBV (hazard ratio (HR) 2.3; P<0.001) and HCV (HR 2.8; P<0.001). CD4 recovery was lower in both HBV and HCV co-infection but only statistically significant for HBV (P<0.001). Discussion HBV and HCV co-infection was associated with worse ART outcomes. The effect of early ART initiation and providing effective treatment for hepatitis co-infection should be explored.

Time for "test and treat" in prevention of mother-to-child transmission programs in low- and middle-income countries.

Abstract: Significant progress has been made in the prevention of mother-to-child transmission (PMTCT) of HIV In 2008, an estimated 1.4 million pregnant women living with HIV in low-and middle-income countries (LMIC) gave birth and almost half of these accessed antiretroviral drugs to prevent HIV transmission to their infants, which ranged from single-dose nevirapine to full combination antiretroviral therapy (ART). Although this represents a significant increase in ART coverage, much more remains to be done in terms of HIV testing and counseling, establishment of ART eligibility, and postnatal treatment and care. In November 2009, the World Health Organization issued new PMTCT guidelines for LMIC, stressing the benefits of earlier initiation of ART during pregnancy and its continuation throughout the delivery and the breastfeeding periods. A key recommendation of these guidelines is to start ART for all HIV positive pregnant women with a CD4 count below 350 cells/mm 3 , irrespective of clinical stage. This makes access to CD4 testing more crucial than ever for the successful implementation of PMTCT programs, since clinical staging performs poorly in identifying pregnant women eligible for ART. However, there are still many barriers to accessing CD4 testing in remote health structures implementing antenatal care services, particularly in countries with a high HIV prevalence. In these settings, universal ART initiation among HIV-positive pregnant women, irrespective of CD4 cell count or clinical staging, is a potentially superior strategy for the prevention of vertical transmission and the improvement of mothers' health.

Digestive disease week 2000. American Association for the Study of Liver Diseases

Abstract: The latest advances in hepatology were presented in oral and poster presentations. In order to cover the varying subspecialties, the sessions were divided into various sections including 'Acute Liver Failure and Artificial Liver Support', 'Biliary Tract and Immunologic Liver Diseases', 'Cellular and Molecular Biology', 'Clinical and Experimental Hepatobiliary Surgery', 'Hepatotoxicity and Cell Death', 'Transport and Biliary Physiology', 'Viral Hepatitis', 'Evaluation and Treatment of Biliary Disease', 'Necrosis/Apoptosis', 'Portal Hypertension', 'Blood Flow and Vascular Disorders of Cirrhosis', 'Liver Transplantation', 'Fibrogenesis', 'Hepatocellular Carcinoma', 'Metabolism and Genetic Disease', and 'Public Policy, Epidemiology and Decision Analysis'. Drug therapy focused on treatments for viral hepatitis, autoimmune hepatitis, primary biliary cirrhosis and primary sclerosing cholangitis, and recurrent viral disease following liver transplant. High dose interferon therapy or various combinations of interferon/ribavirin (ICN Pharmaceuticals Inc) therapy seem to offer the best current therapy for chronic HCV. PEGylated interferon (F Hoffmann-La Roche Ltd) offers hope for treatment and histologic improvement in patients with chronic HCV. Following liver transplantation, combination interferon/ribavirin therapy may also find success, but caution with new potent immunosuppressant monoclonal antibodies is advised. For HBV, intramuscular H-BIG (NABI) appears to be effective and less costly than iv H-BIG administration following liver transplantation. Percutaneous radiofrequency ablation may hold promise over conventional ethanol injection therapy for small hepatocellular carcinoma. Autoimmune hepatitis may respond to tacrolimus therapy whereas budesonide therapy did not provide any advantage to prednisone therapy. For primary biliary cirrhosis, eicosapentate and ursodeoxycholic acid may provide benefit to some patients while silymarin from milk thistle did not provide any additional benefit. In primary sclerosing cholangitis, high dose ursodeoxycholic acid may provide benefit. Ursodeoxycholic acid may also provide benefit for mothers with intrahepatic cholestasis of pregnancy by decreasing pruritus, lowering laboratory values and allowing deliveries to occur closer to term.

The changing epidemiology of liver diseases in the Asia-Pacific region.

Abstract: This Review presents current epidemiological trends of the most common liver diseases in Asia–Pacific countries. Hepatitis B virus (HBV) remains the primary cause of cirrhosis; despite declining prevalence in most Asian nations, this virus still poses a severe threat in some territories and regions. Mortality resulting from HBV infection is declining as a result of preventive measures and antiviral treatments. The epidemiological transition of hepatitis C virus (HCV) infection has varied in the region in the past few decades, but the medical burden of infection and the prevalence of its related cancers are increasing. The lack of licensed HCV vaccines highlights the need for novel treatment strategies. The prevalence of nonalcoholic fatty liver disease (NAFLD) has risen in the past decade, mostly owing to increasingly urbanized lifestyles and dietary changes. Alternative herbal medicine and dietary supplements are major causes of drug-induced liver injury (DILI) in some countries. Complications arising from these chronic liver diseases, including cirrhosis and liver cancer, are therefore emerging threats in the Asia–Pacific region. Key strategies to control these liver diseases include monitoring of at-risk populations, implementation of national guidelines and increasing public and physician awareness, in concert with improving access to health care. Liver diseases exert a substantial disease burden across the Asia–Pacific region. In this Review, the authors explore the epidemiological trends in the most common liver diseases in the region, including HBV infection, HCV infection and nonalcoholic fatty liver disease, and discuss implications for preventive measures.

Plasmodium falciparum parasites lacking histidine-rich protein 2 and 3: a review and recommendations for accurate reporting

Abstract: Malaria rapid diagnostic tests (RDTs) play a critical role in malaria case management, surveillance and case investigations. Test performance is largely determined by design and quality characteristics, such as detection sensitivity, specificity, and thermal stability. However, parasite characteristics such as variable or absent expression of antigens targeted by RDTs can also affect RDT performance. Plasmodium falciparum parasites lacking the PfHRP2 protein, the most common target antigen for detection of P. falciparum, have been reported in some regions. Therefore, accurately mapping the presence and prevalence of P. falciparum parasites lacking pfhrp2 would be an important step so that RDTs targeting alternative antigens, or microscopy, can be preferentially selected for use in such regions. Herein the available evidence and molecular basis for identifying malaria parasites lacking PfHRP2 is reviewed, and a set of recommended procedures to apply for future investigations for parasites lacking PfHRP2, is proposed.

Malaria: The Past and the Present

Abstract: Malaria is a severe disease caused by parasites of the genus Plasmodium, which is transmitted to humans by a bite of an infected female mosquito of the species Anopheles. Malaria remains the leading cause of mortality around the world, and early diagnosis and fast-acting treatment prevent unwanted outcomes. It is the most common disease in Africa and some countries of Asia, while in the developed world malaria occurs as imported from endemic areas. The sweet sagewort plant was used as early as the second century BC to treat malaria fever in China. Much later, quinine started being used as an antimalaria drug. A global battle against malaria started in 1955, and Croatia declared 1964 to be the year of eradication of malaria. The World Health Organization carries out a malaria control program on a global scale, focusing on local strengthening of primary health care, early diagnosis of the disease, timely treatment, and disease prevention. Globally, the burden of malaria is lower than ten years ago. However, in the last few years, there has been an increase in the number of malaria cases around the world. It is moving towards targets established by the WHO, but that progress has slowed down.

HIV-hepatitis B virus coinfection: epidemiology, pathogenesis, and treatment.

Abstract: HIV infection has a significant impact on the natural history of chronic hepatitis B virus (HBV) infection, with increased levels of HBV DNA, accelerated progression of liver disease and increased liver-associated mortality compared with HBV monoinfection. Widespread uptake and early initiation of HBV-active antiretroviral therapy has substantially improved the natural history of HIV-HBV coinfection but the prevalence of liver disease remains elevated in this population. In this paper, we review recent studies examining the natural history and pathogenesis of liver disease and seroconversion in HIV-HBV coinfection in the era of HBV-active antiretroviral therapy and the effects of HIV directly on liver disease. We also review novel therapeutics for the management of HBV with a particular emphasis on clinical strategies being developed for an HBV cure and an HIV cure and their impact on HIV-HBV coinfected individuals.