Trends in biomedical research in Namibia: 1995-2009

Research publications are often used as proxies for the scientific progress and development of a particular country. Country-specific bibliometric studies reflect national strategies to build capacity in tertiary education, research, and health services. In Namibia, no study to date has analyzed trends at the country level. The aim of this study was to evaluate the biomedical publication patterns in Namibia between 1995 and 2009. Using the keyword 'Namibia' in PubMed and ISI Web of Knowledge, resulting papers were hand searched for information on subject areas, types of studies undertaken, first authorship patterns, and institutions involved in biomedically-focused publications. This study identified 450 publications between 1995 and 2009. Only 129 (28.6%) involved Namibian authors. Just over half (58%) of the studies were carried out in Namibia but varied dramatically by subject area. 52% of Namibian-authored papers were Namibian first-authored with a decreasing trend since 2004. Only 7.5% (34) of the publications involved authors from Namibian universities. Namibia has a strong potential to develop in biomedical research but there is a need for tertiary institutions to modify current policies, continue to diversify sub- areas and become equipped to build capacity with local and international collaborators.Peer reviewedEntomology and Plant Patholog

Knowledge and practices of residents in two north Namibian towns with regard to rabies and pet care

Recent studies have highlighted the epidemiology of rabies in southern Africa and the unique nature of kudu rabies in Namibia. However, the serious effect on human populations in northern Namibia lacks focused attention. This study surveyed knowledge and awareness of rabies, including its prevention and pet care in two towns in the Oshana Region of Namibia. Of the 245 interviewed, two thirds owned at least one dog, while a third owned a cat. Eighty-one per cent allowed their animals to roam freely, while 14% reported having been bitten by a dog. The majority of those surveyed recognised that rabies is caused by a virus (53%), identified a dog bite as the main means of transmission (90.6%), cited wild animals as reservoirs (75.5%) and knew that dogs and jackals are significant reservoirs (96.3%). Only 35 (14.3%) identified the correct answers to all four questions. Most of the study participants (63.3%) received their information about rabies from the media. While 83% knew that free vaccines are available at government offices, only 37% had vaccinated their pets, and only 6% had been vaccinated themselves. The results indicate a general understanding of rabies, but focused education efforts are needed with respect to community members in order for specific points to be clarified. The high level of knowledge of vaccine availability, but low coverage, indicates the need for mobilisation with regard to at-risk populations. By building on what is already known, future programmes should successfully reach populations throughout northern Namibia and control rabies in the future.Peer reviewedEntomology and Plant Patholog

Flea-borne rickettsioses: ecologic considerations.

Ecologic and economic factors, as well as changes in human behavior, have resulted in the emergence of new and the reemergence of existing but forgotten infectious diseases during the past 20 years. Flea-borne disease organisms (e.g., Yersinia pestis, Rickettsia typhi, R. felis, and Bartonella henselae) are widely distributed throughout the world in endemic-disease foci, where components of the enzootic cycle are present. However, flea-borne diseases could reemerge in epidemic form because of changes in vector-host ecology due to environmental and human behavior modification. The changing ecology of murine typhus in southern California and Texas over the past 30 years is a good example of urban and suburban expansion affecting infectious disease outbreaks. In these areas, the classic rat-flea-rat cycle of R. typhi has been replaced by a peridomestic animal cycle involving, e.g., free-ranging cats, dogs, and opossums and their fleas. In addition to the vector-host components of the murine typhus cycle, we have uncovered a second typhuslike rickettsia, R. felis. This agent was identified from the blood of a hospitalized febrile patient and from opossums and their fleas. We reviewed the ecology of R. typhi and R. felis and present recent data relevant to the vector biology, immunology, and molecular characterization and phylogeny of flea-borne rickettsioses

General population and medical student perceptions of good and bad doctors in Mozambique

Context: A key element of the doctor-patient relationship is to understand the patient's and doctor's perceptions of quality care.Objectives: To assess the perceptions of good and bad doctors among first-year medical students and local community members in a semi-urban, African setting.Methods: Using open-ended and closed dichotomous questions, 115 first-year medical students in Beira, Mozambique were surveyed regarding their perceptions of a 'good' and 'bad' doctor. Students then surveyed 611 community members in a predominately poor, semi-urban neighbourhood.Results: Answers to open-ended questions provided by both groups produced the same four most important positive characteristics, with good diagnostic and therapeutic skills and dedication ranked highest. Closed-ended questions revealed that local community members felt that being concerned/considerate and diagnosing well were equally important (19.5% and 17.5%, respectively) compared to students (17.5% and 41.2%, respectively). The most important negative characteristics to the open-ended question for both groups were discrimination and contemptuous behaviour: 29.3% for community members and 27.4% for students. The biggest difference between groups was poor attending skills: 17.3% by community members and 3.9% by medical students.Conclusion: This study highlights differences and similarities between the perceptions of medical students and community members concerning a 'good' and a 'bad' doctor. Our data suggest that perceptions are guided by the experiences and values of those interviewed. Results indicate that medical education in developing countries should focus on patient-centered care, including communication skills and attitudes, besides training knowledgeable doctors.Peer reviewedEntomology and Plant Patholog

Olfactory responses of Amblyomma maculatum to rumen fluid and other odourants that attract blood-seeking arthropods

Amblyomma maculatum Koch (Ixodida: Ixodidae) has emerged as a significant vector of human and companion animal diseases in the U.S.A. When expanding in range, A. maculatum can be difficult to collect in the field and control on livestock. A novel method is needed to improve the field collection of A. maculatum, as well as to control their effects as ectoparasites of livestock and companion animals. The present study aimed to test the effects of known volatiles on the activation and selection choices of A. maculatum in a laboratory-based Y-tube assay and field-based assays. Although the majority of adult A. maculatum were activated to move by five of the seven semiochemicals tested, only rumen fluid significantly attracted ticks to make a selection in the Y-tube apparatus. Rumen fluid attracted the most A. maculatum in the laboratory, with 56% (84/150) making it to the rumen Y-tube arm, although the results were not replicated in semi-field experiments. These studies highlight the need for continued work to identify attractants for tick vectors that will assist field collections. These attractants could also be incorporated into management strategies that lead to prevention technologies to reduce tick burdens on cattle or in risk areas of humans.Peer reviewedEntomology and Plant Patholog

Ingestion of Plasmodium falciparum sporozoites during transmission by anopheline mosquitoes

We investigated the process of sporozoite transmission during blood feeding for Anopheles gambiae and An. stephensi experimentally infected with Plasmodium falciparum. When infective mosquitoes were fed 22-25 days postinfection on an anesthetized rat, sporozoites were detected in the midgut of 96.5% of 57 An. gambiae (geometric mean [GM] = 32.5, range 3-374) and in 96.2% of 26 An. stephensi (GM = 19.5, range 1-345). There were no significant differences between species either in salivary gland sporozoite loads or in the number of ingested sporozoites. There was a significant linear relationship between sporozoite loads and the numbers of ingested sporozoites for both An. gambiae (r = 0.38) and An. stephensi (r = 0.69). Subsequently, An. gambiae were tested for sporozoite transmission by allowing them to feed individually on a suspended capillary tube containing 10 ul of blood. A total of 83.3% of 18 infective mosquitoes transmitted a GM of 5.9 (range 1- 36) sporozoites. The same mosquitoes contained a GM of 23.4 (range 2-165) ingested sporozoites. The number of ingested sporozoites was related to sporozoite loads (r = 0.42) but not to the number of sporozoites ejected into capillary tubes. Ingested sporozoites remained in the midgut up to 10 hr after feeding. The comparable numbers of sporozoites ingested by infective mosquitoes in both experiments indicates that the actual number of sporozoites transmitted to the vertebrate host during blood feeding is significantly reduced by the blood ingestion process. The detection of ingested sporozoites by simple methods that avoid contamination by mature oocyst or hemolymph sporozoites may facilitate determinations of the minimal numbers of sporozoites released during blood feeding either by naturally or experimentally infected mosquitoes.Peer reviewedEntomology and Plant Patholog

Morphology and foraging behavior of Oklahoma's grass-feeding termite: Gnathamitermes tubiformans (Isoptera: Termitidae)

Grass-feeding termites, Gnathamitermes sp., can be considered beneficial in pastureland, where they aerate topsoil, recycle nutrients from grasses and forbs, and excavate and redistribute soil. The primary objective of this report is to illustrate and determine the average physical dimensions of Gnathamitermes tubiformans soldiers by measuring key body parts, including left mandible length, as well as discuss observed foraging behavior. G.Tubiformans soldiers have unique mandibles that can be used for accurate identification. Workers are morphologically similar compared with some other arid-land termite species, thus soldier characteristics are used for identification. The secondary objective is to describe observations of G.Tubiformans foraging behavior. This report also provides detailed line drawings and a watercolor illustration for aid in identification. Termites were collected near Temple, Cotton County, Oklahoma, and measured with high precision microscopy. To ensure accurate identification, fourteen different soldier body measurements were determined. The ability to identify termites that are potentially beneficial or detrimental to forage grass biomass production may aid efforts to enhance livestock production on pastures.Peer reviewedEntomology and Plant PathologyPsycholog

Deficiency and Also Transgenic Overexpression of Timp-3 Both Lead to Compromised Bone Mass and Architecture In Vivo

Tissue inhibitor of metalloproteinases-3 (TIMP-3) regulates extracellular matrix via its inhibition of matrix metalloproteinases and membrane-bound sheddases. Timp-3 is expressed at multiple sites of extensive tissue remodelling. This extends to bone where its role, however, remains largely unresolved. In this study, we have used Micro-CT to assess bone mass and architecture, histological and histochemical evaluation to characterise the skeletal phenotype of Timp-3 KO mice and have complemented this by also examining similar indices in mice harbouring a Timp-3 transgene driven via a Col-2a-driven promoter to specifically target overexpression to chondrocytes. Our data show that Timp-3 deficiency compromises tibial bone mass and structure in both cortical and trabecular compartments, with corresponding increases in osteoclasts. Transgenic overexpression also generates defects in tibial structure predominantly in the cortical bone along the entire shaft without significant increases in osteoclasts. These alterations in cortical mass significantly compromise predicted tibial load-bearing resistance to torsion in both genotypes. Neither Timp-3 KO nor transgenic mouse growth plates are significantly affected. The impact of Timp-3 deficiency and of transgenic overexpression extends to produce modification in craniofacial bones of both endochondral and intramembranous origins. These data indicate that the levels of Timp-3 are crucial in the attainment of functionally-appropriate bone mass and architecture and that this arises from chondrogenic and osteogenic lineages

Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

Mosquito ingestion of antibodies against mosquito midgut microbiota improves conversion of ookinetes to oocysts for Plasmodium falciparum, but not P. yoelii

The mosquito midgut is a site of complex interactions between the mosquito, the malaria parasite and the resident bacterial flora. In laboratory experiments, we observed significant enhancement of Plasmodium falciparum oocyst production when Anopheles gambiae (Diptera: Culicidae) mosquitoes were membrane-fed on infected blood containing gametocytes from in vitro cultures mixed with sera from rabbits immunized with A. gambiae midguts. To identify specific mechanisms, we evaluated whether the immune sera was interfering with the usual limiting activity of gram-negative bacteria in An. gambiae midguts. Enhancement of P. falciparum infection rates occurred at some stage between the ookinete and oocyst stage and was associated with greater numbers of oocysts in mosquitoes fed on immune sera. The same immune sera did not affect the sporogonic development of P. yoelii, a rodent malaria parasite. Not only did antibodies in the immune sera recognize several types of midgut-derived gram-negative bacteria (Pseudomonas spp. and Cedecea spp.), but gentamicin provided in the sugar meal 3. days before an infectious P. falciparum blood meal mixed with immune sera eliminated the enhancing effect. These results suggest that gram-negative bacteria, which normally impair P. falciparum development between the ookinete and oocyst stage, were altered by specific anti-bacterial antibodies produced by immunizing rabbits with non-antibiotic-treated midgut lysates. Because of the differences in developmental kinetics between human and rodent malaria species, the anti-bacterial antibodies had no effect on P. yoelii because their ookinetes leave the midgut much earlier than P. falciparum and so are not influenced as strongly by resident midgut bacteria. While this study highlights the complex interactions occurring between the parasite, mosquito, and midgut microbiota, the ultimate goal is to determine the influence of midgut microbiota on Plasmodium development in anopheline midguts in malaria endemic settings.Peer reviewedEntomology and Plant Patholog