Presence and distribution of mosquito larvae predators and factors influencing their abundance along the Mara River, Kenya and Tanzania.

Among all the malaria controlling measures, biological control of mosquito larvae may be the cheapest and easiest to implement. This study investigated baseline predation of immature mosquitoes by macroinvertebrate predators along the Mara River, determined the diversity of predators and mosquito larvae habitats and the range of their adaptive capacity to water physico-chemical parameters. Between July and August 2011, sampling sites (n=39) along the Mara River were selected and investigated for the presence of macroinvertebrate predators and mosquito larvae. The selected sampling sites were geocoded and each dipped 20 times using standard mosquito larvae dipper to sample mosquito larvae, while a D-frame dip net was used to capture the macroinvertebrate predators. Water physico-chemical parameters (dissolved oxygen, temperature, pH, conductivity, salinity and turbidity) were taken in situ at access points, while hardness and alkalinity were measured titrimetically. The influence of macroinvertebrate predator occurrence was correlated with mosquito larvae and water quality parameters using Generalized Linear Model (GLM). Predators (n=297) belonging to 3 orders of Hemiptera (54.2%), Odonata (22.9%) and Coleoptera (22.9%), and mosquito larvae (n=4001) belonging to 10 species, which included An.gambiae s.l (44.9%), Culex spp. (34.8%) and An. coustani complex (13.8%), An. maculipalpis (3.6%), An. phaorensis (1.2%), An. funestus group (0.5%), An. azaniae (0.4%), An. hamoni (0.3%), An. christyi (0.3%), An. ardensis (0.08%), An. faini (0.07%), An. sergentii (0.05%) and 0.05% of Aedes mosquito larvae which were not identified to species level, due to lack of an appropriate key, were captured from different habitats along the Mara river. It was established that invasion of habitats by the macroinvertebrate predators were partially driven by the presence of mosquito larvae (p < 0.001), and the prevailing water physico-chemical parameters (DO, temperature, and turbidity, p <0.001). Understanding abiotic and biotic factors which favour mosquitoes and macroinveterbrate co-occurrence may contribute to the control of malaria.

Distribution and abundance of schistosomiasis and fascioliasis host snails along the Mara River in Kenya and Tanzania.

We purposively selected 39 sampling sites along the Mara River and its two perennial tributaries of Amala and Nyangores and sampled snails. In addition, water physicochemical parameters (temperature, turbidity, dissolved oxygen, conductivity, alkalinity, salinity and pH) were taken to establish their influence on the snail abundance and habitat preference. Out of the 39 sites sampled, 10 (25.6%) had snails. The snail species encountered included Biomphalaria pfeifferi Krauss - the intermediate host of Schistosoma mansoni Sambon, Bulinus africanus - the intermediate host of Schistosoma haematobium, and Lymnaea natalensis Krauss - the intermediate host of both Fasciola gigantica and F. hepatica Cobbold. Ceratophallus spp., a non-vector snail was also encountered. Most (61.0%) of the snails were encountered in streamside pools. Schistosomiasis-transmitting host snails, B. pfeifferi and B. africanus, were fewer than fascioliasis-transmitting Lymnaea species. All the four different snail species were found to be attached to different aquatic weeds, with B. pfeifferi accounting for over half (61.1%) of the snails attached to the sedge, followed by B. africanus and Lymnaea spp., accounting for 22.2 and 16.7%, respectively. Ceratophallus spp. were non-existent in sedge. The results from this preliminary study show that snails intermediate hosts of schistosomiasis and fascioliasis exists in different habitats, in few areas along the Mara River, though their densities are still low to have any noticeable impacts on disease transmission in case they are infected. The mere presence of the vector snails in these focal regions calls for their immediate control and institution of proper regulations, management, and education among the locals that can help curtail the spread of the snails and also schistosomiasis and fascioliasis within the Mara River basin.

Rapid generation of an anthrax immunotherapeutic from goats using a novel non-toxic muramyl dipeptide adjuvant.

BACKGROUND: There is a clear need for vaccines and therapeutics for potential biological weapons of mass destruction and emerging diseases. Anthrax, caused by the bacterium Bacillus anthracis, has been used as both a biological warfare agent and bioterrorist weapon previously. Although antibiotic therapy is effective in the early stages of anthrax infection, it does not have any effect once exposed individuals become symptomatic due to B. anthracis exotoxin accumulation. The bipartite exotoxins are the major contributing factors to the morbidity and mortality observed in acute anthrax infections. METHODS: Using recombinant B. anthracis protective antigen (PA83), covalently coupled to a novel non-toxic muramyl dipeptide (NT-MDP) derivative we hyper-immunized goats three times over the course of 14 weeks. Goats were plasmapheresed and the IgG fraction (not affinity purified) and F(ab')2 derivatives were characterized in vitro and in vivo for protection against lethal toxin mediated intoxication. RESULTS: Anti-PA83 IgG conferred 100% protection at 7.5 mug in a cell toxin neutralization assay. Mice exposed to 5 LD50 of Bacillus anthracis Ames spores by intranares inoculation demonstrated 60% survival 14 d post-infection when administered a single bolus dose (32 mg/kg body weight) of anti-PA83 IgG at 24 h post spore challenge. Anti-PA83 F(ab')2 fragments retained similar neutralization and protection levels both in vitro and in vivo. CONCLUSION: The protection afforded by these GMP-grade caprine immunotherapeutics post-exposure in the pilot murine model suggests they could be used effectively to treat post-exposure, symptomatic human anthrax patients following a bioterrorism event. These results also indicate that recombinant PA83 coupled to NT-MDP is a potent inducer of neutralizing antibodies and suggest it would be a promising vaccine candidate for anthrax. The ease of production, ease of covalent attachment, and immunostimulatory activity of the NT-MDP indicate it would be a superior adjuvant to alum or other traditional adjuvants in vaccine formulations.

A phase I study of the pharmacokinetics and safety of passive immunotherapy with caprine anti-HIV antibodies, (PE)HRG214, in HIV-1-infected individuals.

PURPOSE: To establish the pharmacokinetics and safety of single-dose polyclonal caprine anti-HIV antibodies ((PE)HRG214)in HIV-1-infected individuals. DESIGN: A phase 1, open-label, nonrandomized, dose-escalating study. METHOD: HIV-1-infected patients with CD4+ T-cell counts of < or =200 cells/microL and plasma HIV viral load (VL)of > or =5,000 copies/mL received a single intravenous dose of HRG. Dosing began at 6,000 U/kg HRG with proposed step-wise escalation to 96,000 U/kg. RESULTS: Eleven males were enrolled; median CD4+T-cell count and VL were 96 cells/microL and 126,200 copies/mL, respectively. HRG exhibited linear pharmacokinetics across the dosing range studied. The mean terminal elimination half-life (t(1/2)) was 136.6 +/- 44.6 hours (range, 52.6-198 h). Serum sickness occurred in one 48,000 U/kg HRG recipient. One 6,000 U/kg and two 24,000 U/kg HRG recipients developed a mild rash. Between baseline and day 60, VL remained unchanged (n = 6), increased by 0.67 log(10) copies/mL (n = 1), or declined by 0.34-1.55 log(10) copies/mL (n = 4). CONCLUSION: Single-dose HRG exhibited linear kinetics and a long half-life. Although numbers in each dosing group were very small (n = 3), HRG was generally well tolerated in doses below 48,000 U/kg. Multiple dosing with HRG in the HIV-salvage setting may be complicated by immune-complex formation.

A passive immunotherapy, (PE)HRG214, in patients infected with human immunodeficiency virus: a phase I study.

(PE)HRG214 (HRG) is a polyclonal antibody preparation produced by immunization of goats with purified human immunodeficiency virus (HIV) antigens. In this phase I study, HRG was administered intravenously as a single dose (1, 2, 4, 8, or 16 mg/kg) to 18 HIV-1-infected patients with CD4 cell counts >/=50 cells/microL and virus loads >/=500 copies/mL. The most frequent adverse event was a transient rash, which appeared to be both dose- and CD4 cell count-dependent. At the 16 mg/kg level, median half-life was 68.4 h, and median C(max) was 392 microg/mL, a level well above that which inhibits HIV in vitro. At that dose level, median and maximum decreases in HIV-1 RNA levels at day 8 were 0.24 log(10) and 0.58 log(10), respectively, and, at day 29, were 0.24 log(10 ) and 2.2 log(10), respectively. HRG, administered as a single dose, is reasonably well tolerated and achieves adequate plasma concentrations.