Emerging threat of Eimeria operational taxonomic units (OTUs) on poultry production.

Coccidiosis is an antagonistic poultry disease which negatively impacts animal welfare and productivity. The disease is caused by an obligate, intracellular protozoon known as Eimeria. Several Eimeria species known to infect chickens have been well documented. However, recent studies have elucidated the emergence of three novel genetic variants or operational taxonomic units (OTUs). The discovery of OTUx, OTUy and OTUz complicates the identification and diagnosis of coccidiosis. OTUs are clusters of unknown or uncultivated organisms that are grouped according to a similarity in DNA sequence to a set of specific gene markers. OTUs have been reported in the Earth's Southern Hemisphere, including Australia, Venezuela, India, Zambia, Uganda, Tanzania, China and Ghana. Elucidating their impact on the poultry industry is fundamental in preventing anticoccidial resistance and to access the potential of OTUs as vaccine candidates to provide cross-protection against similar Eimeria species. The identification of OTUs further decreases the risk of false negative coccidial diagnosis. Therefore, this article reviews the importance and risk imposed by OTUs, coupled with their prevalence and geographical distribution in chickens globally.

A review of Eimeria antigen identification for the development of novel anticoccidial vaccines.

Coccidiosis is a major poultry disease which compromises animal welfare and costs the global chicken industry a huge economic loss. As a result, research entailing coccidial control measures is crucial. Coccidiosis is caused by Eimeria parasites that are highly immunogenic. Consequently, a low dosage of the Eimeria parasite supplied by a vaccine will enable the host organism to develop an innate immune response towards the pathogen. The production of traditional live anticoccidial vaccines is limited by their low reproductive index and high production costs, among other factors. Recombinant vaccines overcome these limitations by eliciting undesired contaminants and prevent the reversal of toxoids back to their original toxigenic form. Recombinant vaccines are produced using defined Eimeria antigens and harmless adjuvants. Thus, studies regarding the identification of potent novel Eimeria antigens which stimulate both cell-mediated and humoral immune responses in chickens are essential. Although the prevalence and risk posed by Eimeria have been well established, there is a dearth of information on genetic and antigenic diversity within the field. Therefore, this paper discusses the potential and efficiency of recombinant vaccines as an anticoccidial control measure. Novel protective Eimeria antigens and their antigenic diversity for the production of cheap, easily accessible recombinant vaccines are also reviewed.

Chicken anemia virus: A deadly pathogen of poultry.

Chicken infectious anemia (CIA) is an immunosuppressive disease that causes great economic loss in poultry industry globally. This disease is caused by chicken anemia virus (CAV), an icosahedral and single-stranded DNA virus that is transmitted both vertically and horizontally. CAV, which belongs to the genus Gyrovirus has been reported in human, mouse and dog feces. Rapid identification of different strains of gyrovirus with high similarity to CAV has heightened public concern on this virus. Clinical symptoms of this disease such as intramuscular hemorrhage, weight loss, anemia and bone marrow aplasia are prominent in young chickens, while adult chickens experience subclinical symptoms. Biosecurity measures such as good management practice and vaccination have been the most reliable control strategy against this virus. Therefore, this study reviews the current state of CAV under the following subheadings (i) Chicken anemia virus (ii) Pathogenesis of CAV (iii) Serological evaluation of host antibodies to CAV (iv) Association of Marek's disease and infectious bursa disease with CAV infection (v) Genetic diversity and phylogenetics of CAV strains (vi) Current and future vaccine strategy in the control of CAV. In conclusion, improvement on DNA and recombinant vaccines strategy could curtail the economic impact of CAV on poultry birds. Keywords: adjuvant; CAV; chicken; disease.

Use of discriminant analysis for the evaluation of coccidiosis resistance parameters in chickens raised in hot humid tropical environment.

Coccidiosis endemicity remains a major challenge in poultry production in the tropics and all over the world. In order to develop predictive tool for identification of chickens that are at risk of coccidiosis among Nigerian indigenous chickens, body weight gain (BWG) and hematological variables were determined for chickens infected with Eimeria tenella (female = 60, male = 63) and uninfected (female = 51, male = 45). The hematological variables analyzed include the following: packed cell volume (PCV, %), white blood cells (WBC, × 106/µl), and red blood cells (RBC, × 106/µl), as well as differential leucocyte percentages of neutrophils, lymphocytes, monocytes, and eosinophils. Body weight gain was determined at days 3, 6, 9, 12, and 15. Of the 12 variables analyzed, BWG at day 3, monocyte, PCV, and WBC in males and BWG at days 6, 9, and 12, PCV, and WBC in female chickens showed significant (P ≤ 0.01) difference between the infected and uninfected. Stepwise discriminant analysis evolved a model that could distinguish uninfected from Eimeria-infected chickens. Packed cell volume, WBC, BWG at day 3, and lymphocytes emerged the most discriminant between uninfected and Eimeria-infected chickens in male chickens. In female chickens, PCV, RBC, and BWG at day 3 were identified as most discriminant variables in separating the uninfected from Eimeria-infected chickens. Therefore, this study suggests that routine blood test and estimates of body weight gain could serve as a useful tool for identifying chickens that may be at risk of coccidiosis, enabling improvement of preventive measures.

Dengue virus specific Immunoglobulin G antibodies among patients with febrile conditions in Osogbo, Southwestern Nigeria.

Dengue fever is becoming one of the major public health problems in the world and its distribution has been premised on the migration of people from infected regions. This study was carried out to determine the prevalence of dengue virus IgG antibody among the patients with febrile conditions attending health facilities in Osogbo metropolis, Southwestern Nigeria. The blood samples collected between July and September, 2014 were tested for Plasmodium falciparum and the sera were subsequently subjected to Enzyme Linked Immunosorbent Assay (ELISA) to detect the dengue virus IgG antibody. Of the hundred consented participants screened, 77% were sero-positive for dengue virus IgG antibody while 41% were positive for P. falciparum. Thirty-three (33%) of the participants were positive for both dengue virus IgG antibody and P. falciparum. No significant difference was found in the prevalence of dengue virus IgG antibody and malaria among the participants (P>0.05). The high prevalence of dengue virus IgG and malaria signifies the need by the government of Osun State to sensitize residents and institute urgent measures to mitigate the resultant effects of morbidity and mortality due to dengue fever and dengue hemorrhagic fever which has hitherto appeared to be alien to the area.

Dengue virus specific Immunoglobulin G antibodies among

Dengue fever is becoming one of the major public health problems in the world and its distribution has been premised on the migration of people from infected regions. This study was carried out to determine the prevalence of dengue virus IgG antibody among the patients with febrile conditions attending health facilities in Osogbo metropolis, Southwestern Nigeria. The blood samples collected between July and September, 2014 were tested for Plasmodium falciparum and the sera were subsequently subjected to Enzyme Linked Immunosorbent Assay (ELISA) to detect the dengue virus IgG antibody. Of the hundred consented participants screened, 77% were sero-positive for dengue virus IgG antibody while 41% were positive for P. falciparum. Thirty-three (33%) of the participants were positive for both dengue virus IgG antibody and P. falciparum. No significant difference was found in the prevalence of dengue virus IgG antibody and malaria among the participants (P>0.05). The high prevalence of dengue virus IgG and malaria signifies the need by the government of Osun State to sensitize residents and institute urgent measures to mitigate the resultant effects of morbidity and mortality due to dengue fever and dengue hemorrhagic fever which has hitherto appeared to be alien to the area.

Effect of dosage and application mode of L-carnitine on plasma lipid and egg-yolk cholesterol of turkeys, hatchability of eggs and post-hatch growth of their offsprings.

The effect of dosage and application mode of L-carnitine on plasma lipid and egg-yolk cholesterol of breeder turkeys, hatchability of eggs and post-hatch growth response was investigated using 180 breeder hens. The hens were assigned to six dietary treatments in a 2 × 3 factorial arrangements of two application modes of L-carnitine (diet and drinking water) supplemented at 0, 50 and 100 ppm (mg/kg or mg/l) levels, respectively. Each treatment was replicated five times with six hens per replicate. Dietary inclusion of 50 ppm L-carnitine showed the lowest (p < 0.01) plasma total cholesterol (TC) and low-density lipoprotein concentration (LDL). Breeder hens offered 50 ppm L-carnitine with no regard to application mode recorded the highest (p < 0.01) plasma high-density lipoprotein (HDL). Hens offered 50 and 100 ppm L-carnitine irrespective of application mode also showed reduced (p < 0.01) egg-yolk TC concentration at 32 weeks of age. Dietary supplementation of 50 ppm L-carnitine for breeder turkeys recorded the lowest (p < 0.01) egg-yolk triglyceride (TG) at 40 weeks of age. Hens offered 50 ppm L-carnitine irrespective of application mode recorded the highest (p < 0.05) hen-day egg production. Incidence of dead-in-shell also reduced (p < 0.05) with increasing dosage of L-carnitine. Dietary supplementation of 50 ppm and oral application in drinking water of 100 ppm L-carnitine for breeder turkeys resulted in highest (p < 0.05) egg fertility. Offsprings from breeder hens fed diets supplemented with L-carnitine recorded no post-hatch mortality. Highest (p < 0.05) post-hatch final live weight and weight gain was obtained with poults obtained from hens fed diet supplemented with 50 ppm L-carnitine. In conclusion, dietary supplementation of 50 ppm L-carnitine for turkey hens showed improved serum lipid profile, egg fertility, reduced dead-in-shell, egg-yolk cholesterol and resulted in improved post-hatch growth performance.

Epidemiological evaluation of onchocerciasis along Ogun River System, southwest Nigeria.

BACKGROUND & OBJECTIVE: Epidemiological studies were carried out to assess the prevalence and community microfilarial load (CMFL) of onchocerciasis after repeated annual treatment with ivermectin along Ogun river System, southwest Nigeria. METHOD: Skin snips were taken from consented participants in 11 selected communities along the River system. The microfilarial load of the community was estimated. RESULTS: The prevalence and CMFL varied significantly in the communities (p <0.05). The prevalence of onchocerciasis ranged from 19.1 to 45.6%, while the CMFL ranged from 0.11 to 1.03 microfilariae per skin snip. The CMFL recorded was <5 microfilariae per skin snip, i.e. recognized by WHO as threshold value in certifying the communities to be free of onchocerciasis as public health problem, thus, signifying the possibility of onchocerciasis elimination in the study area. CONCLUSION: Efforts should therefore be intensified to achieve improved ivermectin coverage and compliance in annual ivermectin treatment in order to completely eliminate onchocerciasis as a public health problem in the studied communities.

Molecular approaches to the identification of Bulinus species in south-west Nigeria and observations on natural snail infections with schistosomes.

The current study considers the distribution of a small sample of 138 Bulinus snails, across 28 localities within eight Nigerian states. Snails were identified using a combination of molecular methods involving both DNA sequencing of a partial cytochrome oxidase subunit 1 (cox1) fragment and restriction profiles obtained from ribosomal internal transcribed spacer (its) amplicons. The results showed that the majority of Bulinus samples tested belonged to the species Bulinus truncatus while only two were Bulinus globosus. The use of RsaI restriction endonuclease to cleave the ribosomal its of Bulinus, as a method of species identification, was adopted for the majority of samples, this being a quicker and cheaper method better suited to small laboratory environments. Polymerase chain reaction (PCR) amplification of the schistosome Dra1 repeat within each of the collected Bulinus samples was employed to determine the extent and distribution of infected snails within the sample areas. Successful amplification of the Dra1 repeat demonstrated that 29.7% of snails were infected with schistosomes. Sequencing of the partial schistosome its from a small subset of snail samples suggested that some snails were either penetrated by both Schistosoma haematobium and Schistosoma bovis miracidia or hybrid miracidia formed from the two species.

Growth performance of Nigerian local chickens in crosses involving an exotic broiler breeder.

Six-hundred-and-seven-day-old chicks were generated from Nigerian local chickens consisting of three genotypes (Normal-feathered; Frizzled-feathered; Naked neck) and an exotic broiler breeder (Anak Titan) to evaluate growth performance for possible meat-type chicken development. Growth parameters measured were body weight, breast girth and keel length on weekly basis for 20 weeks. Effects of sire, dam and chick genotypes were significant (P<0.001) on growth traits. At week 20, chickens sired by the Anak Titan weighed 1,614.82 g followed by Normal-feathered local chickens with body weight of 1,211.32 g. Progenies of Anak Titan and Naked neck dams weighed 1,761.96 and 1,292.80 g at week 20, respectively. Among purebreds, Anak Titan weighed 35.05 g at day-old and had heaviest body weight of 2,360.29 g at 20 weeks compared to the three local strains. The average body weights for the crossbred, Normal-feathered × Anak Titan at day-old and week 20 were 36.39 and 1,577.63 g, respectively. This was followed by Anak Titan × Naked neck with 33.32 g at day-old and 1,514.14 g at week 20. Sex had significant effect (P<0.05) at weeks 16 and 20 with the males having higher mean values than their female counterparts. This study revealed that crosses involving Anak Titan sire × Naked neck dam had highest growth performance, and there was no strain differences among the growth performance of purebred Nigerian local chickens.

Population dynamics of indoor sampled mosquitoes and their implication in disease transmission in Abeokuta, south-western Nigeria.

BACKGROUND & OBJECTIVES: A longitudinal study was carried out to investigate the species composition, seasonal abundance, parity and feeding preference of indoor sampled mosquitoes in Abeokuta, south-western Nigeria. METHODS: The mosquitoes were sampled weekly from five stratified locations using Center for Disease Control (CDC) light-traps between August 2005 and July 2006. The mosquitoes were examined for abdominal condition and dissected for age composition. Microscopic and precipitin techniques were also employed for the determination of host blood source. RESULTS: A total of 2969 mosquitoes which belong to 10 species of mosquitoes were collected during the study period. Mansonia africana (35.65%) constituted the most abundant species followed by Culex quinquefasciatus (32.23%) and Anopheles gambiae complex (13.52%). Other species in decreasing order of abundance were Coquilletidia maculipennis (8.2%), Aedes albopictus (5.9%), Ae. aegypti (1.93%), M. uniformis (1.81%), Cx. duttoni (0.25%), Cx. tigripes (0.25%) and An. funestus (0.25%). Seasonal abundance revealed a significant difference (p <0.05) in the population of mosquito vectors collected during the wet season as compared to the dry season and their abundance was positively correlated with rainfall. The results showed that the majority of the vector species collected were unfed and nulliparous. Moreover, the blood meal test was positive for human blood. CONCLUSION: The preponderance of mosquitoes observed in the study is of public health concern since they serve as vectors of most tropical diseases including malaria.

Larvicidal efficacy of seed oils of Pterocarpus santalinoides and tropical Manihot species against Aedes aegypti and effects on aquatic fauna.

Botanical larvicides have featured prominently as alternative to synthetic chemical insecticides which are less degradable and toxic to non-target organisms. The larvicidal potentials of the seed oils of Pterocarpus santalinoides and Tropical Manihot species (TMS 30572) were investigated in the laboratory against larvae of Aedes aegypti. The seed oil of each plant was extracted using n-hexane and was graded into different concentrations; 30, 60, 90, 120 and 150 ppm. The toxicity of each of the concentrations was evaluated against 3rd instar larvae of A. aegypti and tadpoles (Buffo spp) as non target aquatic fauna. Both oils were toxic to the larvae though at higher concentrations (120 ppm and 150 ppm) after 24 hours of exposure. The oil of P. santalinoides was more toxic to the larvae (LC50 104.0 ppm and LC90 184.5 ppm) than oil of TMS (LC50 113.5 and LC90 201.2) but the difference in the lethal doses was not statistically significant (P > 0.05). However, mortality was not recorded at any of the graded concentrations in both oils against tadpoles. The results therefore suggest that the seed oils of both plants could be incorporated as botanical insecticides against mosquito vectors with high safety to non-target organisms.

Morphometric studies on Culex quinquefasciatus and Mansonia africana (Diptera: Culicidae) in Abeokuta, south-western Nigeria.

Some of the important mosquito species are generally sympatric in terms of their geographical distributions, and are difficult to identify based solely on examination of adult females using the available morphological keys. In this study, adult mosquitoes were collected indoors in Abeokuta in south-western Nigeria between August 2005 and July 2006 using Center for Disease Control light traps. The objective was to investigate possible morphological differences in populations of Culex quinquefasciatus and Mansonia africana. Six morphological characters namely, wing length, antennal length, proboscis length, foreleg length, mid leg length and hind leg length were measured in the two species. A total of 868 Cx quinquefasciatus and 962 M. africana were collected during the study period. The mean length was observed to be higher in most characters during the wet season than the dry season but the variation was not statistically significant (P > 0.005). In M. africana, the antennal length, proboscis length, foreleg length and midleg length showed one peak each. The wing length exhibited three peaks while hind leg length showed two peaks. For Cx quinquefasciatus, the antennal length, proboscis length, foreleg length, mid leg length and hind leg length indicated one peak. The wing length however showed three peaks. Each of the peaks observed in wing length and hind leg length of M. africana and wing length of Cx quinquefasciatus was assumed to be a specific population. The coefficient of differences (CDs) for each population indicated the presence of three populations in M. africana (CD > 1.28). However, the hind leg length showed that the two populations were the same (CD < 1.28). Three populations were also obtained from CD for wing leg length of Cx quinquefasciatus (CD > 1.28). Other characters indicated the presence of only one population. The results therefore underscore the need to investigate the status of the two species in relation to species complex.

Mosquito larval habitats and public health implications in Abeokuta, Ogun State, Nigeria.

The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette. The habitats were grouped as ground pools/ponds, gutters/open drains, tyres, domestic containers and treeholes/ leaf axils. Ten species of mosquitoes were encountered in the five habitats namely Mansonia africana, M. uniformis, Culex quinquefasciatus, Aedes aegypti, Ae. albopictus, Ae. vittatus, Cx tigripes, Anopheles gambiae s.l., An. funestus and Eretmapodite clnysogaster. Ae. aegypti bred in all the habitats sampled while Cx quinquefasciatus bred in four habitats except tree holes/leaf axils. An. gambiae s.l and Ae. albopictus occurred in three habitats while other species bred only in one or two habitats. Ground pools and domestic containers recorded the highest number of species followed by gutters/open drains. Tree holes/leaf axils was the least preferred habitat with the lowest number of species occurrence. However, statistical analysis revealed non-significant difference in species occurrence in the five habitats. The availability of the habitats to support the breeding of Aedes, Culex and Anopheles, which are known vectors of urban yellow fever, lymphatic filariasis and malaria suggest that the residents ofAbeokuta City are at risk of mosquito-borne diseases. It is important that residents of the City are enlighten on the environmental factors that contribute to mosquito breeding and that the Government should institute proper sanitation measures to reduce mosquito breeding sites.

Mosquito larval habitats and public health implications in Abeokuta, Ogun State, Nigeria

Abstract: The larval habitats of mosquitoes were investigated in Abeokuta, Nigeria in order to determine the breeding sites of the existing mosquito fauna and its possible public health implications on the residents of the City. The habitats were sampled between August 2005 and July 2006 using plastic dippers and a pipette. The habitats were grouped as ground pools/ponds, gutters/open drains, tyres, domestic containers and treeholes/ leaf axils. Ten species of mosquitoes were encountered in the fi ve habitats namely Mansonia africana, M. uniformis, Culex quinquefasciatus, Aedes aegypti, Ae. albopictus, Ae. vittatus, Cx tigripes, Anopheles gambiae s.l., An. funestus and Eretmapodite clnysogaster. Ae. aegypti bred in all the habitats sampled while Cx quinquefasciatus bred in four habitats except tree holes/leaf axils. An. gambiae s.l and Ae. albopictus occurred in three habitats while other species bred only in one or two habitats. Ground pools and domestic containers recorded the highest number of species followed by gutters/open drains. Tree holes/leaf axils was the least preferred habitat with the lowest number of species occurrence. However, statistical analysis revealed non-signifi-cant difference in species occurrence in the fi ve habitats. The availability of the habitats to support the breeding of Aedes, Culex and Anopheles, which are known vectors of urban yellow fever, lymphatic fi lariasis and malaria suggest that the residents of Abeokuta City are at risk of mosquito-borne diseases. It is important that residents of the City are enlighten on the environmental factors that contribute to mosquito breeding and that the Government should institute proper sanitation measures to reduce mosquito breeding sites