Evolutionary changes in symbiont community structure in ticks.

Ecological specialization to restricted diet niches is driven by obligate, and often maternally inherited, symbionts in many arthropod lineages. These heritable symbionts typically form evolutionarily stable associations with arthropods that can last for millions of years. Ticks were recently found to harbour such an obligate symbiont, Coxiella-LE, that synthesizes B vitamins and cofactors not obtained in sufficient quantities from blood diet. In this study, the examination of 81 tick species shows that some Coxiella-LE symbioses are evolutionarily stable with an ancient acquisition followed by codiversification as observed in ticks belonging to the Rhipicephalus genus. However, many other Coxiella-LE symbioses are characterized by low evolutionary stability with frequent host shifts and extinction events. Further examination revealed the presence of nine other genera of maternally inherited bacteria in ticks. Although these nine symbionts were primarily thought to be facultative, their distribution among tick species rather suggests that at least four may have independently replaced Coxiella-LE and likely represent alternative obligate symbionts. Phylogenetic evidence otherwise indicates that cocladogenesis is globally rare in these symbioses as most originate via horizontal transfer of an existing symbiont between unrelated tick species. As a result, the structure of these symbiont communities is not fixed and stable across the tick phylogeny. Most importantly, the symbiont communities commonly reach high levels of diversity with up to six unrelated maternally inherited bacteria coexisting within host species. We further conjecture that interactions among coexisting symbionts are pivotal drivers of community structure both among and within tick species.

Cryptosporidium oocysts: prevalence in dogs in Abuja, Federal Capital Territory, Nigeria

Cryptosporidium is known to be a zoonotic protozoan parasite, located mainly intracellularly causing the disease called cryptosporidiosis, a diarrheic disease of human and animals. Risk factors for dogs' illness includes exposure to contaminated drinking water from well, borehole and tap water. Hunting as an activity of some dogs serve as a major exposure. The objectives of this study is to determine the prevalence and risk factors associated with fecal shedding of Cryptosporidium oocysts in dogs in Abuja, Federal Capital Territory (FCT). This study was carried out from January to May 2018 in 6 Area Councils of FCT. A total of 400 dogs (213 males and 187 females) aged 0­14 years old were enrolled for this study. The fecal samples collected were examined using Modified Ziehl-Neelsen (MZN) technique. Overall, 91 samples out of 400 were positive, giving a prevalence of Cryptosporidium oocysts infection as 22.75% with 5% degree of freedom. Prevalence among male and female dogs were 27% and 17%, respectively which is statistically significant (p=0.034). Younger puppies had a higher infection rate compared to the older dogs. The infection is relatively higher in local breed of dogs than the cross and pure breeds. This is significantly different (p=0.014). Source of water was also significantly associated with Cryptosporidium infection but food type was found not to be associated. Some of the dogs infected with Cryptosporidium were presented with diarrhoea, though asymptomatic ones can still shed oocysts in the environment. These act as a possible source of infection for other animals.

Haemo- and endoparasites of indigenous chickens reared in Gwagwalada Area Council, Abuja, Nigeria

Poultry production as one of the major sources of protein in Nigeria is constrained by parasitic diseases including haemo- and gastrointestinal (GI) parasites. The haemo- and endoparasites of indigenous chickens reared in Gwagwalada market, Gwagwalada Area Council, Abuja, Nigeria were studied. Blood and fecal samples were collected from 108 chickens (Gallus gallus domesticus) between April­August, 2017. Thin blood smear, and floatation and sedimentation techniques were used for the blood and fecal samples, respectively. Of the 108 local chickens examined, 49 were males, while 59 were females. Overall, female chickens had higher infection rate with haemoparasites (53.1%) that males (46.9%). The blood parasites found mostly were Plasmodium spp., with a prevalence 54.6%, occurring in both male and female chickens examined. It was further revealed that endoparasites infected 60.8% of the female local chicken and 39.2% of the male. The mostly occured Ascaridia spp. with prevalence 35.2%; the least was Strongyloides avium (0.9%). Also, Eimeria spp. occysts were found in 8 (7.4%) of the chickens. This study provides basic information on the haemo- and endoparasites constantly infecting local breed of chickens reared in Gwagwalada Area Council, FCT- Abuja.

Cysticercosis of slaughter cattle in southeastern Nigeria.

The incidence of cysticercosis due to Taenia saginata in both local and exotic breeds of cattle slaughtered for meat in southeastern Nigeria between November 1999 and April 2002 is reported. The examination of various organs of 25,800 cattle in 10 major abattoirs of this region showed that 6750 (26.2%) were infected with Cysticercus (C.) bovis. The prevalence rates varied from one abattoir to another while the rates of cysticercosis in local and exotic breeds varied significantly (P > 0.05). Sixty percent of all the infected animals had cysts. The tongue, cardiac, and masseter muscles were the main predilection sites of the cysts. Out of 11,720 male cattle, examined, 3215 (27.4%) had cysts of C. bovis while 160 (13.6%) of the 1180 female animals investigated were infected. There was an inverse relationship between the ages of the animals and prevalence of infection with C. bovis (r = -0.8743, P < 0.05). Monthly occurrence of the cysts in the animals revealed an upsurge of infected animals during the dry season. The epidemiology and epizootiology of Taenia saginata and C. bovis in relation to the veterinary service agencies and public health planners in southeastern Nigeria are highlighted.

Molecular screening for Midichloria in hard and soft ticks reveals variable prevalence levels and bacterial loads in different tick species.

Candidatus Midichloria mitochondrii, symbiont of the sheep tick Ixodes ricinus, was the first described member of the family Candidatus Midichloriaceae, order Rickettsiales. Recent reports are expanding our view of this family, now including numerous bacteria of great biological and medical interest, indicating a widespread distribution with an increasing range of hosts, with ticks being strongly represented. Here we present a molecular screening of 17 tick species, detecting and quantifying bacteria of the family Midichloriaceae in seven of them, including the first report of a representative of this family in a soft tick species (Argasidae), Ornithodoros maritimus. Based on sequence identity and phylogenetic analysis we propose that all these bacterial symbionts of ticks could be members of the genus Midichloria. The performed screening highlights different prevalence levels and variable bacterial loads in different tick species including one, Ixodes aulacodi, where the bacterium is present in all examined individuals, like in I. ricinus. This result prompts us to hypothesize different roles of Midichloria bacteria in different tick species.

Hematological and plasma biochemistry of the adult wild African grasscutter (Thryonomys swinderianus).

Hematological and plasma biochemical values of wild grasscutters were evaluated to determine their potential to transmit zoonotic pathogens. Three 5-mL blood samples were collected from each of 1000 grasscutters caught in the wild for hematology, biochemical, and parasitological tests. Hematological and biochemical values were compared with those from captive-reared grasscutters. There are significantly (P < 0.05) higher lymphocyte, eosinophil, and basophil values for wild grasscutters compared to those that are captive reared. Parasitological examination revealed a 15% prevalence of blood protozoa in the wild grasscutters. Blood pathogens encountered were Trypanosoma sp. (66.7%) and Plasmodium sp. (33.3%), with 20.7% mixed infection. Sex does not significantly (P > 0.05) affect blood protozoa infection, while season does. We therefore concluded that wild grasscutters serve as efficient reservoir hosts for agents of African trypanosomiasis and malaria in the tropical humid rainforest region of Nigeria.