Emilia Virginia Noormahomed

The emergence of Taenia solium cysticercosis in Eastern and Southern Africa as a serious agricultural problem and public health risk

Pig production has increased significantly in the Eastern and Southern Africa (ESA) region during the past decade, especially in rural, resource-poor, smallholder communities. Concurrent with the increase in smallholder pig keeping and pork consumption, there have been increasing reports of porcine cysticercosis in the ESA region. This article reviews the findings concerning the presence and impact of porcine cysticercosis in seven of the ESA countries. Most of the reported findings are based on surveys utilising lingual palpation and post-mortem examination, however, some also used serological assays. In Tanzania, community-based studies on porcine cysticercosis indicate a prevalence of 17.4% in the northern highlands district of Mbulu and a prevalence range of 5.1-16.9% in the southern highlands. In Kenya recent surveys in the southwestern part of the country where smallholder pig keeping is popular indicate that 10-14% of pigs are positive for cysticercosis by lingual examination. Uganda has the most pigs in Eastern Africa, most of which are kept under smallholder conditions. Preliminary surveys in 1998 and 1999 at slaughterhouses in Kampala indicated a prevalence of porcine cysticercosis between 0.12 and 1.2%, however, a rural survey in northern Uganda in 1999 indicated 34-45% of pigs slaughtered in selected villages were infected. Additionally, a new survey of 297 pigs slaughtered in Kampala in 2002 indicated that pigs from the central region of the country were negative for cysticercosis while 33.7% of the pigs coming from the rural Lira district in the north were positive. Interestingly 8 piglet foetuses removed from an infected slaughtered sow coming from Lira district were all found to harbour cysts of T. solium providing evidence of congenital transmission of porcine cysticercosis. In Mozambique, abattoir records indicate that porcine cysticercosis is present in all provinces of the country. A serological survey on pigs in rural Tete Province found 15% of pigs positive. In Zimbabwe, a retrospective study in official abattoirs around the country from 1994 to 2001 reported a mean prevalence of 0.34% which is in contrast to a post-mortem survey in 1999, which showed that the prevalence of porcine cysticercosis in rural west Zimbabwe where smallholder pig keeping is popular was 28.6%. In Zambia, abattoir records reported porcine cysticercosis in six of the nine provinces. Routine meat inspection of 1316 pigs at a slaughter slab in Lusaka showed that 20.6% of the pigs had cysticercosis whereas serological testing of 874 pigs at the same abattoir indicated that 56.6% were found to have circulating antigens of Taenia solium. Field surveys based on lingual palpation in Southern and Eastern Provinces of Zambia revealed prevalences of 8.2-28.4 and 5.2%, respectively. South Africa has the largest number of pigs in Southern Africa and cysticercosis has been recognised as a problem in the country for many decades. There is strong evidence supporting the high prevalence of neurocysticercosis infecting humans from resource-poor areas of the country where pigs are being raised under smallholder conditions. In spite of this community-based surveys on porcine cysticercosis have never been conducted in South Africa and the last slaughterhouse survey was conducted nearly 40 years ago. The prevalences of porcine cysticercosis found in these ESA countries rank among the highest in the world and the disease is emerging as an important constraint for the nutritional and economic well being of resource-poor smallholder farming communities. The current findings suggest the widespread presence of human tapeworm carriers and thus a high risk of human cysticercosis in both rural areas and urban centres in the ESA region. More research is required in the region to assess the extent and public health and economic impact of T. solium infection in order to determine whether and what prevention and control efforts are needed.

Pooled nucleic acid testing to detect antiretroviral treatment failure in HIV-infected patients in Mozambique

Background:In resource-limited settings, viral load monitoring of HIV-infected patients receiving antiretroviral therapy (ART) is not readily available because of high costs. Here, we compared the accuracy and costs of quantitative and qualitative pooled methods with standard viral load testing. Methods:Blood was collected prospectively from 461 patients receiving first-line ART in Mozambique who had not been evaluated previously with viral load testing. Screening for virologic failure of ART was performed quantitatively (ie, standard viral loads) and qualitatively [one and 2 rounds of polymerase chain reaction (PCR)]. Individual samples and minipools of 5 samples were then analyzed using both methods. The relative efficiency, accuracy, and costs of each method were calculated based on viral load thresholds for ART failure. Results:Standard viral load testing of individual samples revealed a high rate of ART failure (19%–23%) across all virologic failure thresholds, and the majority of the patients (93%) with viral loads >1500 copies per milliliter had genotypic resistance to drugs in their ART regimen. Pooled quantitative screening and deconvolution testing had positive and negative predictive values exceeding 95% with cost savings of

A cross-sectional study of sub-clinical Plasmodium falciparum infection in HIV-1 infected and uninfected populations in Mozambique, South-Eastern Africa

11,250 compared with quantitative testing of each sample individually. Pooled qualitative screening and deconvolution testing had a higher cost savings of

Surgical patients travel longer distances than non-surgical patients to receive care at a rural hospital in Mozambique

30,147 for 1 PCR round and

A Cross-sectional Serological Study of Cysticercosis, Schistosomiasis, Toxocariasis and Echinococcosis in HIV-1 Infected People in Beira, Mozambique

25,535 for 2 PCR rounds compared with quantitative testing each sample individually. Both pooled qualitative PCR methods had positive and negative predictive values ≥90%, but the pooled 1-round PCR method had a sensitivity of 64%. Conclusions:Given the high rate of undiagnosed ART failure and drug resistance in this cohort, it is clear that virologic monitoring is urgently needed in this population. Here, we compared alternative methods of virologic monitoring with standard viral load testing of individual samples and found these methods to be cost saving and accurate. The test characteristics of each method will likely need to be considered for each local population before it is adopted.

Neurocysticercosis in a rural population with extensive pig production in Angónia district, Tete Province, Mozambique

BackgroundPlasmodium falciparum and HIV-1 infection cause substantial morbidity and mortality in sub-Saharan Africa. Increasing evidence suggests these two pathogens interact negatively when infecting the same individual.MethodsA cross-sectional study among HIV-1 infected and uninfected populations was recruited in Mocuba and Maputo, Mozambique to determine the prevalence of sub-clinical malarial parasitaemia using light microscopy and a nested PCR assay.ResultsThe prevalence of sub-clinical P. falciparum parasitaemia was low in Maputo, whether determined by microscopy (0.4%) or PCR (1.9%), but substantially higher in Mocuba (7.6 and 14.7%, respectively). Nested PCR detected nearly 70% more cases of sub-clinical parasitaemia than microscopy, but differences occur by locality. HIV-1 infected persons were more likely to be sub-clinically parasitaemic than HIV-1 uninfected individuals recruited from the same geographic areas. Trimethoprim-sulphamethoxazole use did not substantially reduce sub-clinical parasitaemia.ConclusionsDried blood spots are a convenient and sensitive technique for detecting sub-clinical infection with P. falciparum by nested PCR. Prevalence of P. falciparum is substantially lower in Maputo where malaria control programmes have been more active than in the rural town of Mocuba. In Mocuba, among those presenting for HIV-1 counseling and testing, the prevalence of P. falciparum is substantially higher in those who test positive for HIV-1 than those without HIV-1 infection. The clinical implications of sub-clinical P. falciparum infection among HIV-1 infected persons warrant additional study.

Further characterization of Tsol-p27 as a diagnostic antigen in sub-Saharan Africa

BACKGROUND Surgical care is increasingly recognised as an important component of global health delivery. However, there are still major gaps in knowledge related to access to surgical care in low-income countries. In this study, we compare distances travelled by surgical patients with patients seeking other medical services at a first-level hospital in rural Mozambique. METHODS Data were collected on all inpatients at Hospital Rural de Chókwè in rural Mozambique between 20 June 2012 and 3 August 2012. Euclidean distances travelled by surgical versus non-surgical patients using coordinates of each patients city of residence were compared. Data were analysed using ArcGIS 10 and STATA. RESULTS In total, 500 patients were included. Almost one-half (47.6%) lived in the city where the hospital is based. By hospital ward, the majority (62.0%) of maternity patients came from within the hospitals city compared with only 35.2% of surgical patients. The average distance travelled was longest for surgical patients (42 km) compared with an average of 17 km for patients on all other wards. CONCLUSIONS Patients seeking surgical care at this first-level hospital travel farther than patients seeking other services. While other patients may have access to at community clinics, surgical patients depend more heavily on the services available at first-level hospitals.

Onchocerciasis, an undiagnosed disease in Mozambique: identifying research opportunities

Background Helminthic infections are highly endemic in Mozambique, due to limited access to healthcare and resources for disease prevention. Data on the subclinical prevalence of these diseases are scarce due to the fact that an immunological and imaging diagnosis is not often available in endemic areas. We conducted a cross-sectional study on HIV1+ patients from Beira city in order to determine the seroprevalence of cysticercosis, schistosomiasis, toxocariasis and echinoccocosis and its possible interaction with HIV infection. Methodology/Principal Findings Patients (601) were voluntarily recruited at the Ponta Gea Health Center and their demographic and clinical data were recorded (including CD4+ cell count and antiretroviral regimen). Mean age was 39.7 years, 378 (62.9%) were women and 223 (37.1%) were men. Four hundred seventy-five (475) patients (79%) were already on highly active antiretroviral therapy (HAART), and 90 started therapy after being enrolled in the study. For serological testing we used a Multiplex Western Blot IgG from LDBIO Diagnostics. The overall seroprevalence was 10.2% for cysticercosis, 23% for schistosomiasis, 7.3% for toxocariasis and 17.3% for echinococcosis. Conclusions/Significance Neither age nor the CD4+ count were significantly associated with the seroprevalence of the helminths studied. However, patients with CD4+ between 200–500/µl had a higher seroprevalence to all helminths than those with less than 200/µl cells/and those with more than 500 cells/µl. Female gender was significantly associated with cysticercosis and schistosomiasis, and being in HAART with toxocariasis. Headache was significantly associated with cysticercosis and toxocariasis. There was no association between epilepsy and seropositivity to any of the parasites. The study concluded that a clear understanding of the prevalence and manifestations of these coinfections, how best to diagnose subclinical cases, and how to manage diseases with concomitant antiretroviral therapy is needed.

Innovative Strategies for Transforming Internal Medicine Residency Training in Resource-Limited Settings: The Mozambique Experience

Neurocysticercosis (NCC) is an important neurological disease in countries with high prevalence of Taenia solium infection and is emerging as a serious public health and economic problem. The aim of this study was to estimate the prevalence of NCC in Angónia district, Tete province, Mozambique based on: prevalence of human T. solium cysticercosis assessed by antigen Enzyme-linked Immunosorbent Assay (Ag-ELISA) seropositivity, history of epilepsy, and brain computed tomography (CT) scan results. A cross sectional study was conducted between September and November 2007 in Angónia district. Questionnaires and blood samples were collected from 1,723 study subjects. Brain CT-scans were carried out on 151 study subjects with confirmed history of epilepsy. A total of 77 (51.0% (95% CI, 42.7–59.2)) and 38 (25.2% (95% CI, 18.5–32.9)) subjects met the criteria for definitive and probable diagnosis of NCC, respectively. T. solium Ag-ELISA seropositivity was found in 15.5% (95% CI, 12.8–16.2) of the study subjects. The estimated life time prevalence of epilepsy was 8.8% (95% CI, 7.5–10.2). Highly suggestive lesions of NCC were found on CT-scanning in 77 (71.9%, (95% CI, 62.4–80.2)) of the seropositive and 8 (18.1%, (95% CI, 8.2–32.7)) of the seronegative study subjects, respectively. The present findings revealed a high prevalence of NCC among people with epilepsy in Angónia district. Determination of effective strategies for prevention and control of T. solium cysticercosis are necessary to reduce the burden of NCC among the affected populations.

Near patient CD4 count in a hospitalized HIV patient population

Commercial antigens used to diagnose human neurocysticercosis are obtained from either a soluble parasite extract or a parasite-derived glycoprotein fraction. The aim of the present study was to identify antigenic proteins as potential diagnostic candidates in Mozambique. Soluble proteins from Taenia solium cysticerci were separated by two-dimensional electrophoresis and blotted onto nitrocellulose membranes. Subtracted hybridization was performed with serum samples obtained from patients with neurocysticercosis (NCC) and from a NCC-negative control group. Six antigenic proteins were identified and sequenced by liquid chromatography–mass spectrometry. Among these we found Tsol-p27, which was previously identified as a diagnostic candidate in a study conducted in Nicaragua, Central America. Here, we evaluated Tsol-p27 and the antigen cC1 as potential recombinant diagnostic reagents, and also investigated the localization and partial function of Tsol-p27. Immunoblotting demonstrated that Tsol-p27 was recognized by all 10 serum samples from NCC-positive individuals, whereas cC1 was identified by only five of the 10 positive sera. None of the antigens were recognized by negative control sera. Despite the limited number of serum samples evaluated in this study, the results suggest that Tsol-p27 can be a suitable candidate for diagnosis of human NCC, not only in Central America but also in sub-Saharan Africa.