Population surveys of Nile crocodiles (Crocodylus niloticus) in the Murchison Falls National Park, Victoria Nile, Uganda

1. A 12-month-long survey (April 2013 to March 2014) for Nile crocodiles (Crocodylus niloticus) was conducted along a section of the Victoria Nile/Ramsar site of Murchison Falls National Park, in order to update the historic information on crocodile populations in the area, locating nesting areas, determining seasonality patterns and habitat use, and assess the current abundance and the population size trends since the 1960s. The methods employed included visual encounter surveys, transect counts and opportunistic methods, by using boats.2. In general, there were diurnal and seasonal fluctuations in the number of crocodile sightings. The crocodile sightings peaked between the months of June and August, with the highest mean number of sightings encountered on any single day being 67 (in July 2013), and the second peak was between January and March with  the highest mean of 118 recorded in January 2014. The second peak also coincided with the crocodile breeding  season. This clearly shows that the distribution of the sub-population sampled followed a climatic regime.3. Crocodiles were observed most frequently in water (37%). Grassy banks, islands, river mouths and sandy banks constituted about 47% of the habitats utilised by the crocodile population. Although basking was the most frequent type of activity performed by crocodiles (50%) over the entire survey period, their key activities varied significantly from month to month. Nesting was very visible during the last quarter of the year and the first quarter of the New Year.4. There was a clear decline of the abundance of crocodiles in this population between 1960s and nowadays. This declining trend was obvious also taking into account the various survey methodologies employed over the decades

Bioactivity and toxicity of Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant extracts

Background: Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant species are commonly used in traditional medicine for a number of ailments. The extracts of these plants have been shown to have anti-schistosomal activity suggesting that they could be used for the development of new chemical entities (NCEs) for the treatment of schistosomiasis. However there is limited knowledge on their toxicological profile and their use in traditional medicine may not be a satisfactory safety indication.Methods: In this study the extracts were first screened for bioactivity using brine shrimp lethality test for the determination of LC50 followed by rodent acute toxicity and 28 day subchronic studies.Results: B. micrantha water extract with a LC50 of 77µg/ml was deemed toxic while C. ambrosoides methanol and water extracts were moderately toxic with LC50 of 104.63µg/ml and 696.44µg/ml respectively. O. americanum hexane and water extracts toxicity varied from moderate to slightly toxic with LC50 of 887.59µg/ml and 2254.60µg/ml respectively. C. ambrosoides and O. americanum water extracts which were preferentially selected for subsequent studies were found to have mild to no irritation to rodent eyes and skin. Moreover, the aminotransferases AST and ALT which were used to detect liver injury suggested negligible effect.Conclusions: This therefore confirms that C. ambrosoides and O. americanum water extracts are safe for clinical use with O. americanum water extract having a slight edge

Waterbirds of the Murchison Falls–Albert Delta Wetland System, an important Ramsar site

The Murchison Falls–Albert Delta Wetland System Ramsar Site, declared in 2006, consists of the River Nile from the Murchison Falls up to and including a small part of Lake Albert. Before entering the lake, the river splits into three main channels passing through an extensive delta supporting a papyrus swamp; the Ramsar site also includes the land within a kilometre of the river banks, north and south. Most is within Murchison Falls National Park. The river, including the channels through the papyrus, supports large numbers of waterbirds of many species. For a year, we undertook monthly waterbird counts along the channels through the delta swamps, and on the section of Lake Albert within the Ramsar site. Overall, we recorded 78 waterbird species and the site regularly supports three globally and another seven nationally threatened species, including Shoebill Balaeniceps rex, Grey Crowned Crane Balearica regulorum and Papyrus Gonolek Laniarius mufumbiri. The site is also important for large numbers of White-winged Black Terns Chlidonias leucopterus on passage. Most of the larger species, such as White-faced Whistling Duck Dendrocygna viduata and Long-tailed Cormorant Microcarbo africanus rarely, if ever breed in this area, instead their numbers drop at the times when they are expected to breed, apparently elsewhere. A number of pairs of Fish Eagles Haliaeetus vocifer breed, and there is a small colony of African Darters Anhinga rufa. The large numbers of easily-seen birds attract increasing numbers of visitors, adding to the site’s value. Various industrial activities are planned within the watershed of this Ramsar Site, mainly associated with oil and gas, and our data are expected to provide baseline data for future monitoring of the site. Keywords:  Murchison, Ramsar, waterbirds, Ugand

Trypanosoma

African Animal Trypanosomiasis (AAT) transmitted cyclically by tsetse fly (Glossina spp.) is a major obstacle to livestock production in the tropical parts of Africa. The objective of this study was to determine the infection rates of trypanosomes in Glossina species in Mtito Andei Division, Makueni County, Kenya. Tsetse fly species, G. longipennis and G. pallidipes, were trapped and DNA was isolated from their dissected internal organs (proboscis, salivary glands, and midguts). The DNA was then subjected to a nested PCR assay using internal transcribed spacer primers and individual trypanosome species were identified following agarose gel electrophoresis. Out of the 117 flies trapped in the area 39 (33.3%) were teneral while 78 (67%) were nonteneral. G. pallidipes constituted the largest percentage of 58% while G. longipennis were 42%. The overall trypanosomes infection rate in all nonteneral Glossina spp. was 11.53% with G. longipennis recording the highest infection rate of 23.08% while G. pallidipes had an infection rate of 5.77%. T. vivax was the most infectious (10.26%) compared to T. congolense (1.28%). Mean apparent densities were strongly positively correlated with infection rates (r=0.95) confirming the importance of this parameter as an indicator of AAT transmission risk

Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission

BACKGROUND: Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiological agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect feeding success and possibly reduce tick-borne transmission of T. parva. Here we report the evaluation of a multivalent vaccine cocktail of tick antigens for their ability to reduce R. appendiculatus feeding success and possibly reduce tick-transmission of T. parva in a natural host-tick-parasite challenge model. METHODS: Cattle were inoculated with a multivalent antigen cocktail containing recombinant tick protective antigen subolesin as well as two additional R. appendiculatus saliva antigens: the cement protein TRP64, and three different histamine binding proteins. The cocktail also contained the T. parva sporozoite antigen p67C. The effect of vaccination on the feeding success of nymphal and adult R. appendiculatus ticks was evaluated together with the effect on transmission of T. parva using a tick challenge model. RESULTS: To our knowledge, this is the first evaluation of the anti-tick effects of these antigens in the natural host-tick-parasite combination. In spite of evidence of strong immune responses to all of the antigens in the cocktail, vaccination with this combination of tick and parasite antigens did not appear to effect tick feeding success or reduce transmission of T. parva. CONCLUSION: The results of this study highlight the importance of early evaluation of anti-tick vaccine candidates in biologically relevant challenge systems using the natural tick-host-parasite combination

Population surveys of Nile crocodiles (Crocodylus niloticus) in the Murchison Falls National Park, Victoria Nile, Uganda

1. A 12-month-long survey (April 2013 to March 2014) for Nile crocodiles (Crocodylus niloticus) was conducted along a section of the Victoria Nile/Ramsar site of Murchison Falls National Park, in order to update the historic information on crocodile populations in the area, locating nesting areas, determining seasonality patterns and habitat use, and assess the current abundance and the population size trends since the 1960s. The methods employed included visual encounter surveys, transect counts and opportunistic methods, by using boats. 2. In general, there were diurnal and seasonal fluctuations in the number of crocodile sightings. The crocodile sightings peaked between the months of June and August, with the highest mean number of sightings encountered on any single day being 67 (in July 2013), and the second peak was between January and March with the highest mean of 118 recorded in January 2014. The second peak also coincided with the crocodile breeding season. This clearly shows that the distribution of the sub-population sampled followed a climatic regime. 3. Crocodiles were observed most frequently in water (37%). Grassy banks, islands, river mouths and sandy banks constituted about 47% of the habitats utilised by the crocodile population. Although basking was the most frequent type of activity performed by crocodiles (50%) over the entire survey period, their key activities varied significantly from month to month. Nesting was very visible during the last quarter of the year and the first quarter of the New Year. 4. There was a clear decline of the abundance of crocodiles in this population between 1960s and nowadays. This declining trend was obvious also taking into account the various survey methodologies employed over the decades

Bioactivity and toxicity of Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant extracts

Background: Bridelia micrantha, Chenopodium ambrosoides and Ocimum americanum plant species are commonly used in traditional medicine for a number of ailments. The extracts of these plants have been shown to have anti-schistosomal activity suggesting that they could be used for the development of new chemical entities (NCEs) for the treatment of schistosomiasis. However there is limited knowledge on their toxicological profile and their use in traditional medicine may not be a satisfactory safety indication.Methods: In this study the extracts were first screened for bioactivity using brine shrimp lethality test for the determination of LC50 followed by rodent acute toxicity and 28 day subchronic studies.Results: B. micrantha water extract with a LC50 of 77µg/ml was deemed toxic while C. ambrosoides methanol and water extracts were moderately toxic with LC50 of 104.63µg/ml and 696.44µg/ml respectively. O. americanum hexane and water extracts toxicity varied from moderate to slightly toxic with LC50 of 887.59µg/ml and 2254.60µg/ml respectively. C. ambrosoides and O. americanum water extracts which were preferentially selected for subsequent studies were found to have mild to no irritation to rodent eyes and skin. Moreover, the aminotransferases AST and ALT which were used to detect liver injury suggested negligible effect.Conclusions: This therefore confirms that C. ambrosoides and O. americanum water extracts are safe for clinical use with O. americanum water extract having a slight edge

Herpetofaunal diversity and community structure in the Murchison Falls - Albert Delta Ramsar site, Uganda : Herpetofaunal diversity

1. The area of the Murchison Falls-Albert Delta is among the most important for conservation in East Africa dueto the high species richness, and the presence of several endemic species of conservation concern.2. Here, we report a study on the diversity patterns and community structure of the herpetofauna of this area.3. Field studies were conducted in the Albert Nile Delta Ramsar site between 1st October 2017 and 9th September2018. The data collection relied on Visual Encounter Surveys (VES), pitfall trapping, and dip netting. Descriptive statistics, i.e. species numbers in each transect were used as a measure of the present biodiversity, whereasChao1 and Chao species estimator algorithms were used to predict the potential number of species found ineach site/habitat.4. A total of 898 individuals representing 25 reptile species belonging to four orders, 15 families, and 20 generawere recorded during the 12 months of surveys.5. The data shows some non-random spatial and temporal patterns whereby there is a cyclic reptilian diversitypeaking during the December-March and again towards June-August-September which are peaks of the dryseason.6. The most frequently encountered species were Varanus niloticus, Crocodylus niloticus, Agama agama, Trachylepis maculilabris, and Lygodactylus guttularis, which accounted for almost 90% of all recorded individuals.7. A total of 27 amphibian species, belonging to nine families and 10 genera were recorded during the periodof the survey. The diversity and abundance graphs would indicate amphibians having bimodal peaks (September-December, and March-May). The diversity seemed to dip during the dry season months – which is theopposite case for reptiles