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The Bawa Health Initiative (BHI) was established in 2005 with the goal of initiating a comprehensive public health care program in Bawa, a rural village in the West region of Cameroon. Interventions undertaken include a comprehensive helminth control program, provision of water filters, sanitary latrines, insecticide-treated bed nets, and a health education program. Data gathered from citizens of Bawa during Dec 2017, were obtained from the Sophie Awounke Community Health Center in Bawa, Cameroon. These data including prevalence of geohelminth infection, morphometric data, and hemoglobin concentrations were compared to data gathered in previous surveys conducted by BHI in 2007 and 2010 to assess the effectiveness of interventions implemented by the organization. All metrics indicate substantial improvement in the overall health of the citizens of Bawa, evidenced by decreases in the occurrence of anemia, prevalence of malnourished, undernourished and stunted individuals and in the prevalence and intensity of geohelminths. These data strongly suggest that public health interventions implemented by BHI have been effective in reducing the burden of disease and increasing the overall well-being of the citizens of Bawa, Cameroon and surrounding villages.Keywords: Ascariasis, trichuriasis, hookworm infection

Leishmaniasis is a vector-borne parasitic disease caused by protozoa of the genus Leishmania. Twenty different species are known to cause disease in humans with varying degrees of pathology. These diseases are transmitted throughout the geographic range of phlebotomine sandflies, found between the latitudes 50°N and 40°S. This study explores antibody dependent enhancement (ADE) as the cause of disease exacerbation in heterologous exposure of L. major primed mice to L. infantum challenge. BALB/c mice received serum from L. major infected or naive mice. All mice were challenged with L. infantum and tissue parasite burdens were recorded. Animals that received anti-L. major serum exhibited significantly higher parasite burdens. Surprisingly, these parasite burdens were higher than those of mice infected with L. major and challenged with L. infantum. In vitro phagocytosis assays were carried out to measure parasite uptake in the presence of naive vs. anti-L. major serum. J774A.1 murine monocytes were cultured with either L. major or L. infantum in the presence of anti-L. major serum, naive serum, or no serum. Significantly higher rates of L. major uptake by J774A.1 cells occurred in the presence of anti-L. major serum, but no measurable increase of L. infantum phagocytosis was seen. Our results suggest that increased disease severity observed in vivo in mice previously exposed to L. major and challenged with L infantum is not a result of extrinsic ADE. We speculate that intrinsic ADE, due to biased memory T cell responses caused by Fcγ signaling, could account for disease exacerbation seen in the animal model.

The US Southwest plant Dalea parryi (Fabaceae) was investigated as part of an ongoing study of the potential of plant compounds for anthelmintic activity to the human pathogenic hookworm Ancylostoma ceylanicum. This has resulted in the isolation of three previously undescribed isoflavonoid metabolites, denoted parryans A-C, a chalcone, six pterocarpans, and three known compounds from the roots of D. parryi. Parryans A and B express a rarely-seen O-prenyl substituent. Structures of the previously undescribed compounds were established using 1D and 2D NMR spectroscopy and mass spectrometry. The relative and absolute configurations of the undescribed stereoisomers were assigned using chemical shift and coupling constant data and comparisons of specific rotations to published data. The most active of the isolated compounds only expressed a 17% reduction in survival of A. ceylanicum adult hookworm in an ex vivo assay at 50 μg/mL after 5 days exposure. Toxicity, ranging from 47 to 93% reduction in survival of mammalian splenocytes was expressed by four of the compounds.

A flexible and cost-effective method for the highly functional group-compatible and site-selective cross-coupling of readily affordable α-chloro-β-formyltetrahydropyridines has been developed, under nickel or cobalt catalysis, leading to the rapid synthesis of 2,3,5,6-tetrasubstituted dehydropiperidines bearing α-amino allylic stereocenters. Cobalt-catalyzed reductive cross-coupling of chloro enaminals with electronically-diverse bromostyrenes as coupling partners proceeds in good yields and with high E/Z selectivity to afford Diels-Alder-suitable cross-conjugated 1,3-dienes.

Leishmaniasis is endemic in northern Cameroon. However, the sand fly vectors have not been incriminated. A sand fly species inventory was generated by integrating a number of techniques. Miniature light traps were used for collecting sand flies in a variety of ecotopes found across the area, and a morphological and molecular identification approach for taxonomic confirmation was undertaken. In a pilot survey conducted in September 2012, we captured 687 sand flies, 259 of which were morphologically identified to species level. They represent 14 species of the genera Sergentomyia and Grassomyia. No Phlebotomus spp. were found. A second series of collections was carried out during 2013 in five different environmental setups: two urban, two peri-urban/rural and one sylvatic; 14,036 sand flies (6665 males and 7371 females) were collected. A total of 5926 females and 98 males were morphologically identified to species level, representing 19 species of the genera Sergentomyia, Grassomyia and Phlebotomus, including Ph. duboscqi, a known vector of cutaneous leishmaniasis in the region. Two new taxa were found and are described: Sergentomyia (Sintonius) thomsoni mandarai ssp. nov. and Se. coronula sp. nov. Our study is the first to report the following species in Cameroon: Se. (Sin.) thomsoni (as ssp. nov. mandarai), Se. (Ser.) cincta, Se. (Sin.) affinis ssp. vorax, Se. (Sin.) adami, Se. (Sin.) herollandi, and Se. (Sin.) christophersi. In addition, some morphologically atypical Sergentomyia specimens (combination of Ser. x Sin. traits) were recorded. A checklist of 32 species reports from Cameroon is presented.

Objectives A sound knowledge of the vector-host-parasite transmission dynamics is a prerequisite for adequate control measures of vector-borne diseases. To achieve this, an entomological investigation was conducted in the cutaneous leishmaniasis (CL) endemic focus of Mokolo District, northern Cameroon to identify the insect vector(s) of the disease. Methods Phlebotomine sand flies were collected in and around Mokolo using New Standard CDC Miniature Light Traps. Individual sand flies were used for morphological species identification, and the remainder of the body for DNA analysis. Sand flies were demonstrated to harbour Leishmania spp. parasites using ITS1 PCR. Mitochondrial vertebrate-specific Cytochrome b -PCR was used to identify blood meals ingested by female sand flies. PCR amplicons were sequenced for Leishmania and blood sources discrimination. Results This study revealed the presence of Leishmania donovani complex DNA (n = 1) in Phlebotomus duboscqi and of lizard-borne Leishmania tarentolae-like DNA (n = 3) in Sergentomyia spp. in 79 sand fly specimens from Mokolo district. Conclusions The causative agent of CL could not be detected in potential vectors. Instead, we found evidence for visceral leishmaniasis (VL) parasites in Phlebotomus duboscqi as well as enzootic reptile parasites in the Mokolo area. We recommend that an epidemiological survey be carried out in the area to evaluate the prevalence and eventually describe the clinical manifestations of VL in the human population. Political instability in neighbouring countries and the resulting refugee migration are likely explanations for the emergence of VL in Mokolo.

Cutaneous leishmaniasis (CL) patients coinfected with HIV are known to show a more severe, prolonged course of disease; the immunological basis is not known. We now assessed clinical features, sera and skin biopsies of HIV(+) and HIV(-) patients with CL to identify drivers of increased susceptibility to Leishmania. CL lesion numbers, surface, and healing duration were significantly increased in HIV(+) as compared to HIV(-) patients (2.5, 14 and4-fold, respectively). Patients with HIV infection exhibited lower serum Leishmania-specific IgG levels and decreased IL-6 and IL-8. Most importantly, dramatically decreased numbers of CD4(+) T cells (approximately eightfold), but not CD8(+) cells, together with fewer CXCR3(+) Th1 cells, fewer Foxp3(+) effector/regulatory T cells, and reduced levels of IFN-γ expression were found in lesional skin. Our findings suggest that compromised CD4(+) T-cell responses may be responsible for worsened disease outcome leading to defects in parasite elimination in the absence of sufficient numbers of IFN-γ-producing Th1 cells.

Hookworms are ubiquitous human parasites, infecting nearly one billion people worldwide, and are the leading cause of anemia and malnutrition in resource-limited countries. Current drug treatments rely on the benzimidazole derivatives albendazole and mebendazole, but there is emerging resistance to these drugs. As part of a larger screening effort, using a hamster-based ex vivo assay, anthelmintic activity toward Ancylostoma ceylanicum was observed in the crude extract of aerial parts of Dalea ornata. These studies have led to the isolation and characterization of phenolic metabolites 1–10. The structures were determined by 1D and 2D NMR spectroscopy, and the absolute configuration of 1 was assigned using electronic circular dichroism data. The new compound, (2S)-8-(3-methylbut-2-en-1-yl)-6,7,4′-trihydroxyflavanone (1), was weakly active at 7.3 µM, with 17% reduction in survival of the hookworms after 5 days. The rotenoids deguelin (9) and tephrosin (10), predictably perhaps, were the most active, with complete worm mortality observed by day 4 (or earlier) at 6.3 and 6.0 µM, respectively. The effects of 1–10 on hookworm motility and on toxicity to hamster splenocytes were also explored as important measures of treatment potential.

The geographic distribution of Leishmania major overlaps with several other species of Leishmania. This study seeks to examine what effect previous exposure to L. major has on the outcome of infection with Leishmania infantum, the agent of virulent visceral leishmaniasis. The L. major immune response is well characterized by a strong Th1 response leading to resolution and protection against subsequent re-infection. A contrasting Th2 immune response leads to disseminated disease, while the role Th17 cytokines may play in Leishmania infection is still being explored. The cytokine profile, antibody titer, and parasite burden were evaluated in the susceptible BALB/c mouse after L. infantum infection in either naïve mice or those previously infected with a low/self-healing dose of L. major. Only IL-4 expression in mice previously exposed to L. major was found to be significantly increased over controls, a cytokine with an ambiguous role in L. infantum infection. However, disease exacerbation, with a notably higher parasite burden, was observed in the L. major exposed mice compared to the L. infantum only. Cross-reactive antibodies were seen in both groups of infected mice regardless of their immune history. Studies have shown a role for opsonizing antibodies leading to increased disease in visceral leishmaniasis. We speculate that cross-reactive antibodies may be playing a role in augmenting visceral disease in mice with immunological memory to L. major.

A survey of human geohelminth infections was conducted in Bawa and Nloh, two rural agrarian villages in the West Province of Cameroon. The purpose of the study was to provide baseline data to assess the efficacy of a universal geohelminth control program that the Bawa Health Initiative, a nongovernmental humanitarian organization, has implemented in the 2 villages. In Nloh, A. lumbricoides, T. trichiura, and hookworm exhibited prevalences of 33.0%, 54.3%, and 26.6%, respectively, and mean intensities given as eggs per gram of feces (epg) of 2,490, 246, and 293, respectively. In Bawa, A. lumbricoides, T. trichiura, and hookworm exhibited prevalences of 15.3%, 41.5%, and 18.7%, respectively, and mean intensities of 18,904, 346, and 57 epg, respectively. All geohelminths investigated exhibited extreme overdispersion. Although the 2 villages are demographically nearly identical, prevalences of A. lumbricoides and T. trichiura infection in Nloh were significantly higher than those in Bawa. The only differences between the villages that might account for the differences in prevalence of geohelminth infection is that clean drinking water and basic sanitation, and hygiene education programs, have been implemented in Bawa. High prevalences of infection in senior adults indicate that they may represent a neglected group in regard to geohelminth infection. In Bawa, a clustering of moderate- to high-intensity infections was noted among family compounds for A. lumbricoides and T. trichiura. Comparison of these data to those gathered in the West Province of Cameroon during a Cameroonian National Survey of helminth infections, conducted between 1985-1987, suggests that the prevalences of infection with A. lumbricoides and T. trichiura have decreased while the incidence of hookworm infection may have increased. However, such comparisons between surveys must be interpreted very conservatively, given the multitude of factors leading to dramatic differences in prevalence of geohelminth infections, even

The prevalence of the waterborne protozoan parasites Entamoeba histolytica/dispar, Giardia lamblia, and Cryptosporidium parvum were investigated in Nloh and Bawa, 2 rural agrarian villages in the West Province of Cameroon, Africa. The purpose of this study was to gather baseline data prior to the installation of biosand water filters in Nloh and to determine the prevalence of these parasites in Nloh and Bawa. Human stool samples were collected during June 2007, (85 from Nloh and 114 from Bawa) and tested utilizing the Triage Micro Parasite Panel® for the presence of the aforementioned protozoans. In Nloh, prevalences of E. histolytica/dispar, G. lamblia, and C. parvum were 15.7%, 14.5%, and 3.6%, respectively; and 7.1%, 1.8%, and 0.0% in Bawa, respectively. There were no significant differences in prevalence among age groups or between genders. The prevalence of G. lamblia was significantly lower in Bawa than in Nloh. However, no significant difference was detected in the prevalences of E. histol...

In visceral leishmaniasis, the draining LN (DLN) is the initial site for colonization and establishment of infection after intradermal transmission by the sand fly vector; however, little is known about the developing immune response within this site. Using an intradermal infection model, which allows for parasite visceralization, we have examined the ongoing immune responses in the DLN of BALB/c mice infected with Leishmania infantum. Although not unexpected, at early times post-infection there is a marked B-cell expansion in the DLN, which persists throughout infection. However, the characteristics of this response were of interest; as early as day 7 post-infection, polyclonal antibodies (TNP, OVA, chromatin) were observed and the levels appeared comparable to the specific anti-leishmania response. Although B-cell-deficient JhD BALB/c mice are relatively resistant to infection, neither B-cell-derived IL-10 nor B-cell antigen presentation appear to be primarily responsible for the elevated parasitemia. However, passive transfer and reconstitution of JhD BALB/c with secretory immunoglobulins, (IgM or IgG; specific or non-specific immune complexes) results in increased susceptibility to L. infantum infection. Further, JhD BALB/c mice transgenetically reconstituted to secrete IgM demonstrated exacerbated disease in comparison to WT BALB/c mice as early as 2 days post-infection. Evidence suggests that complement activation (generation of C5a) and signaling via the C5a receptor (CD88) is related to the disease exacerbation caused by IgM rather than cytokine levels (IL-10 or IFN-gamma). Overall these studies indicate that polyclonal B-cell activation, which is known to be associated with human visceral leishmaniasis, is an early and intrinsic characteristic of disease and may represent a target for therapeutic intervention.

SUMMARY Hookworm infection is associated with anaemia and malnutrition in many resource-limited countries. Ancylostoma hookworms have previously been shown to modulate host cellular immune responses through multiple mechanisms, including reduced mitogen-mediated lymphocyte proliferation, impaired antigen presentation ⁄ processing, and relative reductions in CD4 + T cells in the spleen and mesenteric lymph nodes. Syrian hamsters were depleted of CD4 + for up to 9 days following intraperitoneal injection (200 lg) of a murine antimouse CD4 monoclonal IgG (clone GK1AE5). CD4 + T-cell

Most parasitic skin infections are averted by very efficient strategies of preventing pathogen invasion. Innate immune cells such as mast cells, macrophages and dendritic cells are responsible for detecting parasites and for recruiting proinflammatory cells that help to contain and control the pathogen at sites of infection. This induces efficient adaptive immunity, which is crucially important for parasite control. Using the example of cutaneous leishmaniasis, we highlight how the skin utilizes different strategies to prevent skin infection and how containment of the infection to the skin site may reduce the harm that otherwise may result for the entire organism.

Hookworm infection is a major cause of anemia and malnutrition in resource-poor countries. Human and animal studies suggest that infection with these intestinal nematodes is associated with impaired cellular immunity, characterized by reduced lymphocyte proliferation in response to both parasite and heterologous antigens. We report here data from studies aimed at defining mechanisms through which hookworms modulate the host cellular immune response. Splenocytes and mesenteric lymph node (MLN) cells from hamsters infected withAncylostoma ceylanicumshowed minimal proliferation in response to mitogen at days 20 and 30 postinfection (p.i.), with partial recovery noted at day 70 p.i. The proliferative capacity of enriched splenocyte T-cell preparations from infected animals following stimulation with hookworm antigens was partially restored in the presence of antigen-presenting cells from uninfected hamsters. Analysis by fluorescence-activated cell sorting revealed that hookworm infection is associated with reduced percentages of both CD4+and surface immunoglobulin G-positive lymphocytes in the spleen and MLN cells. Splenocytes from infected hamsters also secreted more nitric oxide (NO) in culture than did those from naïve animals. Inhibition of NO secretion was associated with partial restoration of the proliferative capacity of splenocytes from infected animals in response to concanavalin A, suggesting a role for NO in mediating this effect. Together, these data demonstrate that hookworm infection is associated with impaired function of antigen-presenting cells and depletion of important lymphocyte subpopulations and also suggests a role for NO in parasite-induced immunosuppression.

Texto completo: acesso restrito. p. 7–12 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-01-14T15:22:53Z No. of bitstreams: 1 Lucas Pedreira de Carvalho.pdf: 114743 bytes, checksum: dfbcf3fe3bbc3654b7c18cab2903f62d (MD5) Approved for entry into archive by Flávia Ferreira (flaviaccf@yahoo.com.br) on 2014-01-20T15:45:48Z (GMT) No. of bitstreams: 1 Lucas Pedreira de Carvalho.pdf: 114743 bytes, checksum: dfbcf3fe3bbc3654b7c18cab2903f62d (MD5) Made available in DSpace on 2014-01-20T15:45:48Z (GMT). No. of bitstreams: 1 Lucas Pedreira de Carvalho.pdf: 114743 bytes, checksum: dfbcf3fe3bbc3654b7c18cab2903f62d (MD5) Previous issue date: 2003 Leishmaniases have a high prevalence in tropical countries. In order to improve existing diagnostic systems based on total Leishmania proteins, and to identify antigen candidates for vaccine development, an intensive search for the identification of antigens was performed using molecular biology techniques. In this study, the immune response to three L. infantum recombinant antigens was evaluated. Upon stimulation with KMP11, mononuclear cells from leishmaniasis patients produced high levels of IL-10, while a predominant IFN-γ production could be observed in cultures stimulated with H2A and soluble Leishmania antigen. All the recombinant antigens induced very little IL-5. KMP11 decreased IFN-γ production by 48% in cultures of peripheral blood mononuclear cells from cutaneous leishmaniasis patients who had been stimulated with soluble Leishmania antigen. Furthermore, antibodies to KMP11 were detected in the sera from all patients with visceral leishmaniasis and in the majority of the sera from patients with cutaneous leishmaniasis or individuals with asymptomatic L. chagasi infection. Thus, KMP11 is recognized by cells and sera of patients with different clinical forms of leishmaniasis, and KMP11, through IL-10 production, proved to be a potent antigen in modulating type 1 immune response.

Approximately one billion people are currently infected with hookworm. Despite its high prevalence and the concomitant immune suppression seen in infected individuals, little research has been done on the mechanism of immunosuppression by hookworm. Our study focused on characterizing mechanisms utilized by hookworm to suppress the host immune response. Splenocytes and draining lymph node cells from mice injected with hookworm excretory/secretory (ES) proteins showed decreased proliferation in response to both heterologous and species-specific antigens while also having increased nitric oxide secretion. Analysis by fluorescence-activated cell sorting revealed that mice injected with ES had reduced percentages of CD4+ T cells indicating potential effects of ES proteins on lymphocyte homeostasis. Antibody and cytokine responses analysis demonstrated that immunization with ES proteins decreased IgG and IgG1 levels, also decreased interleukin (IL-) -4 and increased IL-12 and interferon-gamma (IFN-γ) cytokine production suggesting impairment of B cell activation and a shift towards a non-healing IL-12 directed T helper-1 immune response. Together, these data demonstrate that host immunosuppression by hookworms is orchestrated by ES proteins and provide mechanisms underlying the shift towards a non-healing Th-1 profile as seen in humans suffering from hookworm infection. This article is protected by copyright. All rights reserved.

Two studies were undertaken to determine the species composition of the phlebotomine sandfly fauna in the Mokolo region, an endemic focus of cutaneous leishmaniasis in northern Cameroon. The preliminary survey conducted in July 1994 using sticky paper traps recorded 843 sandfly specimens, all belonging to the two genera of the Old World sandflies, Sergentomyia and Phlebotomits. The species included S. (Sergentomyia) schzvetzi, S. (Sergentomyia) antennata, S. (Parrotomyia) africana and P. (Phlebotomus) duboscqi: From January 1996 to December 1996, a total of 3241 sandflies were collected using sticky paper traps. In this sampling, six out of the total of eight species recorded were of the genus Sergentomyia. In addition to the species recorded in the preliminary study, S. (S.) bedfordi, S. (Grassomyia) squamipleuris, S. (Sintonius), clydei and P. (Anaphlebotomus) rodhaini were sampled in 1996. This is the first report of S. squamipleuris ir Cameroon. The implications of this study to the transmission of cutaneous leishmaniasis are discussed with particular reference to P. duboscqi, a known vector of the disease in the region.

Cutaneous leishmaniasis (CL) is endemic in Central Africa, including Cameroon. However, data on its prevalence and co-infection with HIV are scarce. Here we present the results of a large cross-sectional study reporting the prevalence, clinical features and species identification of CL and HIV co-infection in northern Cameroon. A total of 32 466 subjects were clinically screened for CL during a door-to-door survey, followed by parasitological diagnosis in the field laboratory. Amongst the subjects surveyed, 146 (0.4%) were diagnosed with active CL. Seven (4.8%) of these 146 CL patients tested positive for HIV-1 and/or HIV-2. The number of lesions per CL patient ranged from 1 to 20. Three of the five subjects with >10 active lesions were co-infected with HIV. In both CL and HIV co-infected subjects, three successful parasite isolates were identified as Leishmania major by PCR. This first report of L. major/HIV co-infection in Cameroon and Central Africa confirms the endemicity of CL in the region and highlights a worsened CL pathology in HIV co-infected individuals. These findings provide important data necessary for the development and implementation of successful control programmes against CL and HIV in this geographical area.

Heterologous prime-boost vaccination employing DNA-vaccinia virus (VACV) modality using the Leishmania homologue of receptors for activated C kinase (LACK) (p36) antigen has been shown to elicit protective immunity against both murine cutaneous and visceral leishmaniasis. However, DNA priming is known to have limited efficacy; therefore in the current study the effect of NKT cell activation using alpha-galactosyl-ceramide (alphaGalCer) during intradermal DNAp36 priming was examined. Vaccinated mice receiving alphaGalCer + DNAp36 followed by a boost with VVp36 appeared to be resolving their lesions and had at ten- to 20-fold higher reductions in parasite burdens. NKT cell activation during alphaGalCer + DNAp36 priming resulted in higher numbers of antigen-reactive effector CD4(+) and CD8(+) T cells producing granzyme and IFN-gamma, with lower levels of IL-10. Although immunodepletion studies indicate that both CD4 and CD8 T cells provide protection in the vaccinated mice, the contribution of CD4(+) T cells was significantly increased in mice primed with DNAp36 together with alphaGalCer. Notably 5 months after boosting, mice vaccinated with DNAp36 + alphaGalCer continued to show sustained and heightened T cell immune responses. Thus, heterologous prime-boost vaccination using alphaGalCer during priming is highly protective against murine cutaneous leishmaniasis, resulting in the heightened activation and development of CD4 and CD8 T cells (effector and memory T cells).

This study reports the efficacy of a heterologous prime-boost vaccination using DNA and vaccinia viruses (Western Reserve [WR] virus and modified [attenuated] vaccinia virus Ankara [MVA]) expressing the LACK antigen ( Leishmania homologue of receptors for activated C kinase) and an intradermal murine infection model employing Leishmania infantum . At 1 month postinfection, vaccinated mice showed high levels of protection in the draining lymph node (240-fold reduction in parasite burden) coupled with significant levels of gamma interferon (20 to 200 ng/ml) and tumor necrosis factor alpha/lymphotoxin (8 to 134 pg/ml). Significant but lower levels of protection (6- to 30-fold) were observed in the spleen and liver. Comparable levels of protection were found for mice boosted with either LACK-WR or LACK-MVA, supporting the use of an attenuated vaccinia virus-based vaccine against human visceral leishmaniasis.