Morphological and molecular characterization of Amblyomma variegatum (Acari: Ixodidae) ticks from Nigeria

The association of most tick-borne pathogens with specific tick species has made it imperative that proper identification and characterization of such tick vectors is necessary for the purpose of developing effective tick and tick-borne control strategies. This study was undertaken to identify and characterize Amblyomma species ticks collected from cattle in Plateau State, North-Central, Nigeria. They were morphologically identified using diagnostic characters. Further confirmation and characterization was done genetically using a 460bp-long partial fragment of the 16S rRNA gene amplified by polymerase chain reaction (PCR). The amplified fragment was cloned and sequenced for the phylogenetic dendogram. All the examined ticks were identified as A. variegatum which was confirmed by 16S rRNA gene sequences analysis, and phylogenetic inferences showed a 99% similarity and grouping to A. variegatum of African origin. However, the A. variegatum sequences from Nigeria were clustered into 2 groups, but formed a distinct clade from the A. variegatum sequence from Ethiopia. This study was able to conclusively identify and characterize A. variegatum ticks from the study areas by utilizing morphology and molecular genotyping based on sequencing of the 16S rRNA gene.Keywords: Amblyomma variegatum, Morphology, 16S rRNA, PCR, Sequencin

Ultrastructure of secretory cells in the gut of the cattle-tick Boophilus microplus

The ultrastructural study of the secretory cells type 1 and 2 confirmed the separate identities of two secretory cell types in the gut of female B. microplus. Secretory cell type 1 (s1) synthesized and secreted large, spherical, uniformly electrondense granules. Secretory cell type 2 (s2) synthesized smaller, irregularly shaped and more complex granules. Another cell type, the basophilic cell, was shown to be the reorganized basal remnant of secretory cell s2. A few of the basophilic cells retained remnant s2 granules within their cytoplasm. In these cells the reorganized cisternae of rough endoplasmic reticulum were arranged in whorls and parallel arrays. The cells synthesized granules with a different ultrastructure and position in the cell from the earlier granules. The new secretory material may be egg proteins which are released into the haemolymph, and transported to the ovary. Another secretory cell type with smaller spherical granules was seen in the gut caeca of only two female ticks and more evidence is needed to prove its separate identity

Immunization of cattle against Boophilus microplus using extracts derived from adult female ticks: Histopathology of ticks feeding on vaccinated cattle

Immunization of cattle against Boophilus microplus using extracts derived from adult female ticks: histopathology of ticks feeding on vaccinated cattle. International Journal for Parasitology 16: 35-41. Histological examination of the tick Boophilus microplus fed on cattle vaccinated with tick extract showed that the gut was the primary site of damage. Within 24-48 h of attachment digest cells were either sloughed off into the lumen or were completely destroyed leaving only the basal lamina and muscle layer. Subsequent rupture of the gut allowed host leucocytes to enter the haemocoel and attack other tissues. After 6 days the surviving ticks showed a delay in development of digest cells and gut basophilic cells. Many host leucocytes had escaped into the haemolymph and these cells destroyed tick muscle and Malpighian tubules but not salivary glands. Females which survived to post-engorgement also had damaged gut cells. In males the histopathology of the gut was similar but the accessory gland of the reproductive organ was also damaged by host leucocytes. These effects on feeding ticks were not found on control cattle and have not been reported on animals with naturally acquired resistance to tick infestations. Vaccination apparently stimulated a different mechanism of resistance to ticks

Research trends and prevalence of Cryptosporidium infections in animals in Nigeria: A review

Cryptosporidiosis is a zoonotic infection caused by apicomplexan protozoan parasite Cryptosporidium spp. and is characterized by acute gastrointestinal infections in developing countries including Nigeria. Previous studies have established its incidences in some states of Nigeria. Due to paucity of information on its overall prevalence across the country, we used published data to discuss the findings of cryptosporidiosis in different animal species and their distribution from eight reported States (Borno, Kaduna, Kebbi, Ogun, Osun, Oyo, Plateau, Sokoto) and the Federal Capital Territory (FCT) in Nigeria. Of these States, goats in Ogun State had the highest prevalence of 76.5%, followed by pigs (44.9%), whilst dogs in Oyo had the lowest prevalence rate of 0.9%. The review results revealed that 14 different species were observed affecting different animals with C. paruvm and C. hominis as the dominant zoonotic spp. Global and local control strategies for effective management of this disease were discussed. This review provides current research references for further understanding the prevalence of cryptosporidiosis inNigeria, its epidemiological characteristics for prevention and also for public health importance of transmission in animals and in controlling the disease in Nigeria.Keywords: apicomplexan protozoan; epidemiological characteristics; Nigeri

Transmissão transovariana de Babesia bovis em Boophilus microplus: obtenção de cepa de carrapato livre de Babesia spp. Babesia bovis transovarian transmission in Boophilus microplus: obtention of a Babesia free tick strain

O presente trabalho objetivou o estudo de parte do ciclo da Babesia bovis no seu hospedeiro invertebrado, o carrapato Boophilus microplus. Analisou-se a capacidade de infeccção e transmissão transovariana de B. bovis em partenóginas de B. microplus, alimentadas em bovinos portadores e enfermos por esse protozoário. No 18º dia após a infestação, coletaram-se partenóginas diretamente do corpo dos bovinos e teleóginas após o desprendimento natural, a partir do 21º dia. Todos os grupos foram incubados a 27ºC e umidade relativa superior a 70%. No 5º dia após o início da postura, realizou-se o exame de hemolinfa a fim de diagnosticar a infecção dos ínstares por B. bovis. A ausência de infecção detectada no exame de hemolinfa foi confirmada posteriormente com o teste biológico, revelando que partenóginas não transmitem B. bovis transovarianamente. Esses resultados oferecem uma técnica simplificada para a obtenção de cepas de carrapatos livres de B. bovis.<br>In this experiment part of the life cycle of Babesia bovis in its invertebrate host, the tick Boophilus microplus was studied. In order to evaluate the capacity of infection and transmission of B. bovis were collected semi-engorged females of B. microplus fed on carrier and ill bovines. In the 18th day after infestation, semi-engorged females were collected directly from bovine bodies and after 21st day engorged females dropped on the ground. All the collected groups were incubated at 27°C and relative humidity greater than 70%. At the 5th day of oviposition the diagnosis was made by direct examination of haemolymph smears. The biological test reveled that B. bovis transovarial transmission doesn't happer in semi-engorged females. The results offer a simple techique to obtain strains of ticks free of B. bovis