Molecular identification of bloodmeal sources and trypanosomes in Glossina spp., Tabanus spp. and Stomoxys spp. trapped on cattle farm settlements in southwest Nigeria.

The interactions of host, vector and parasite in bovine trypanosomiasis transmission cycles in southwest Nigeria are not yet well understood. Trypanosoma (Trypanosomatida: Trypanosomatidae) species infection prevalences and bloodmeal sources were determined in transmitting vectors of the genera Glossina (Diptera: Glossinidae), Tabanus (Diptera: Tabanidae) and Stomoxys (Diptera: Muscidae) collected using Nzi traps in cattle settlements in southwest Nigeria. Sequenced cytochrome B mitochondrial DNA segments obtained from vector digestive tracts identified bloodmeal sources from eight host species, namely human, cattle, hippopotamus, giraffe, gazelle, spotted hyena, long-tailed rat and one unidentified species. Overall, 71.1% [95% confidence interval (CI) 63.0-78.1], 33.3% (95% CI 21.9-47.0) and 22.2% (95% CI 16.2-29.9), respectively, of Glossina, Tabanus and Stomoxys flies were positive for trypanosomes. The observed trypanosome species were Trypanosoma vivax, Trypanosoma congolense, Trypanosoma brucei, Trypanosoma evansi, Trypanosoma simiae and Trypanosoma godfreyi. Trypanosome DNA was more prevalent in tsetse (34.8% Tr. vivax, 51.1% Tr. b. brucei, 5.2% Tr. congolense, 4.4% Tr. simiae and 24.4% mixed infections) than in other flies and the main determinants in all flies were seasonal factors and host availability. To the best of the present group's knowledge, this is the first report of Trypanosoma species in Tabanus and Stomoxys flies in Nigeria. It indicates that vector control programmes should always consider biting flies along with tsetse flies in the control of human and animal trypanosomiasis.

People, Patches, and Parasites: The Case of Trypanosomiasis in Zimbabwe.

Understanding the socio-ecology of disease requires careful attention to the role of patches within disease landscapes. Such patches, and the interfaces between different socio-epidemiological systems, we argue, have important implications for disease control. We conducted an interdisciplinary study over three years to investigate the spatial dynamics of human and animal trypanosomiasis in the Zambezi valley, Zimbabwe. We used a habitat niche model to identify changes in suitable habitat for tsetse fly vectors over time, and this is related to local villagers' understandings of where flies are found. Fly trapping and blood DNA analysis of livestock highlighted the patchy distribution of both flies and trypanosome parasites. Through livelihoods analysis we explored who makes use of what areas of the landscape and when, identifying the social groups most at risk. We conclude with a discussion of the practical implications, including the need for an integrated 'One Health' approach involving targeted approaches to both vector control and surveillance.

Brucellosis in Sub-Saharan Africa: Current challenges for management, diagnosis and control.

Brucellosis is a highly contagious zoonosis caused by bacteria of the genus Brucella and affecting domestic and wild mammals. In this paper, the bacteriological and serological evidence of brucellosis in Sub-Saharan Africa (SSA) and its epidemiological characteristics are discussed. The tools available for the diagnosis and treatment of human brucellosis and for the diagnosis and control of animal brucellosis and their applicability in the context of SSA are presented and gaps identified. These gaps concern mostly the need for simpler and more affordable antimicrobial treatments against human brucellosis, the development of a B. melitensis vaccine that could circumvent the drawbacks of the currently available Rev 1 vaccine, and the investigation of serological diagnostic tests for camel brucellosis and wildlife. Strategies for the implementation of animal vaccination are also discussed.

Echinococcus granulosus infection in dogs in Sidi Kacem Province (North-West Morocco).

This study was undertaken in the Province of Sidi Kacem in northwest Morocco between April 2010 and March 2011. The main objective of the study was to determine the prevalence of Echinococcus granulosus (Eg) infection in owned dogs. This province was selected as a case study because of the social conditions, geographic and climatic diversity making it a model representative of many parts of Morocco. The survey was carried out in 23 rural communes and in the 5 municipalities (urban districts) of the Province and sampling was undertaken in randomly selected households. A total of 273 owned dogs comprising 232 from the 23 rural communes (rural dogs) and 41 from the 5 municipalities (urban dogs) were tested. Arecoline hydrobromide purgation was selected as the diagnostic method of choice to enable visualisation of expelled worms by dog owners, thereby imparting messages on the transmission mode of Eg to humans and farm animals. Of the 273 dogs tested, purgation was effective in a total of 224 dogs (82.1%). The overall estimated prevalence of Eg infection was 35.3% (79/224, 95% CI 22.3-47.0%). Dogs inhabiting rural communes were at greater risk of infection (38.0%, 95% CI 31.1-45.3%) than dogs roaming in municipalities or urban areas (18.8%, 95% CI 7.2-36.4%) and the prevalence of infection was higher in those inhabiting rural communes with slaughterhouses (62.7%, 95% CI 48.1-75.9%) than in communes without (29.1%, 95% CI 21.7-37.2%). This first assessment of Eg infection in Sidi Kacem Province indicates a key role of rural slaughterhouses in parasite transmission to dogs.

Integrated health messaging for multiple neglected zoonoses: Approaches, challenges and opportunities in Morocco.

Integrating the control of multiple neglected zoonoses at the community-level holds great potential, but critical data is missing to inform the design and implementation of different interventions. In this paper we present an evaluation of an integrated health messaging intervention, using powerpoint presentations, for five bacterial (brucellosis and bovine tuberculosis) and dog-associated (rabies, cystic echinococcosis and leishmaniasis) zoonotic diseases in Sidi Kacem Province, northwest Morocco. Conducted by veterinary and epidemiology students between 2013 and 2014, this followed a process-based approach that encouraged sequential adaptation of images, key messages, and delivery strategies using auto-evaluation and end-user feedback. We describe the challenges and opportunities of this approach, reflecting on who was targeted, how education was conducted, and what tools and approaches were used. Our results showed that: (1) replacing words with local pictures and using "hands-on" activities improved receptivity; (2) information "overload" easily occurred when disease transmission pathways did not overlap; (3) access and receptivity at schools was greater than at the community-level; and (4) piggy-backing on high-priority diseases like rabies offered an important avenue to increase knowledge of other zoonoses. We conclude by discussing the merits of incorporating our validated education approach into the school curriculum in order to influence long-term behaviour change.

The neglected zoonoses--the case for integrated control and advocacy.

The neglected zoonotic diseases (NZDs) have been all but eradicated in wealthier countries, but remain major causes of ill-health and mortality across Africa, Asia, and Latin America. This neglect is, in part, a consequence of under-reporting, resulting in an underestimation of their global burden that downgrades their relevance to policy-makers and funding agencies. Increasing awareness about the causes of NZDs and how they can be prevented could reduce the incidence of many endemic zoonoses. Addressing NZDs by targeting the animal reservoir can deliver a double benefit, as enhanced animal health means a reduced risk of infection for humans, as well as improved livelihoods through increased animal productivity. Advocacy for NZD control is increasing, but with it comes a growing awareness that NZD control demands activities both in the short term and over a long period of time. Moreover, despite the promise of cheap, effective vaccines or other control tools, these endemic diseases will not be sustainably controlled in the near future without long-term financial commitment, particularly as disease incidence decreases and other health priorities take hold. NZD intervention costs can seem high when compared with the public health benefits alone, but these costs are easily outweighed when a full cross-sector analysis is carried out and monetary/non-monetary benefits--particularly regarding the livestock sector--are taken into account. Public-private partnerships have recently provided advocacy for human disease control, and could prove equally effective in addressing endemic zoonoses through harnessing social impact investments. Evidence of the disease burdens imposed on communities by the NZDs and demonstration of the cost-effectiveness of integrated control can strengthen the case for a One Health approach to endemic zoonotic disease control.

Current initiatives in One Health: consolidating the One Health Global Network.

The Global Response to Avian Influenza has led to a longer-term One Health movement, which addresses risks, including zoonoses, at the human-animal- environment interface, and requires the development of innovative partnerships at the political, institutional and technical levels. One Health is a sustainable and rational option when the cumulative effects of health hazards on food and economic security are considered, but demands long-term financial investment. Projections of growth in the demand for livestock production and consumption in Asia and Africa also call for effective One Health responses. However, an effective response also requires validated evidence of the socio-economic value that the One Health approach can provide. Implementing the One Health approach depends on forging strong links between human and animal health services, the environment and public policy. The authors present a list of some of the national and transnational partnerships established since 2006. Political support, good governance and effective policies and networks are crucial building blocks for One Health sustainability. The Global Response to Avian Influenza was initially established under the joint leadership of the European Union, the United States and the United Nations System Influenza Coordination Office. Since then it has supported numerous initiatives, including the World Health Organization (WHO)/Food and Agriculture Organization of the United Nations (FAO)/World Organisation for Animal Health (OIE) Global Early Warning System (GLEWS). Indeed, the Global Response to Avian Influenza paved the way for an unprecedented WHO/FAO/OIE tripartite partnership, which promoted the integration of foodborne, neglected zoonotic and tropical diseases within the One Health movement and led to the tripartite High-Level Technical Meeting of 2011 in Mexico. The One Health Global Network, which began as a proposition at an Expert Consultation in Winnipeg, Canada, in 2009, is now a reality. While its Global Guidance Group takes shape, the choice of soft-governance--an approach which relies more on information and advisory guidelines than on hierarchy and legislation, and which aims to steer local organisations rather than to control them--remains challenging. Nonetheless, the emergence of One Health as a professional and academic discipline, together with the growing references to a One Health culture, also offers new opportunities.

Latent Trypanosoma brucei gambiense foci in Uganda: a silent epidemic in children and adults?

Trypanosoma brucei gambiense sleeping sickness follows a long asymptomatic phase and persists in ancient foci from which epidemic clinical disease arises. A putative focus of T. b. gambiense infections has been identified, initially in mothers and young children, on the Lake Albert shoreline of Western Uganda leading to mass screening of 6207 individuals in September 2008. T. b. gambiense infections were identified by Card Agglutination Test for Trypanosomiasis (CATT) and sub-species-specific PCR although parasitological methods failed to confirm any patent trypanosome infections. In April 2009, CATT positives were re-visited; diagnosis of individuals by CATT and PCR was unstable over the two time points and parasites remained undetected, even using mini Anion Exchange Centrifugation Technique (mAECT). These observations suggest the possibility of a silent focus of disease, where all infected individuals are in a latent stage, and highlight our limited understanding of the local natural history and disease progression of T. b. gambiense in children and adults.

Spatial variation of tick abundance and seroconversion rates of indigenous cattle to Anaplasma marginale, Babesia bigemina and Theileria parva infections in Uganda.

Tick abundance and seroconversion rates of 640 indigenous cattle in a mixed crop-livestock system in Uganda were investigated in a 14 months longitudinal study. Up to 100% of the cattle in Buyimini, Kubo, Nanjeho, Ojilai and Sitengo villages (high tick challenge zone) were consistently infested with Rhipicephalus appendiculatus, whereas on average 50% of the cattle in Bunghaji, Hitunga and Magoje villages (low tick challenge zone) were inconsistently infested. Likewise, up to 50% of the cattle in Buyimini, Kubo, Nanjeho, Ojilai and Sitengo villages were consistently infested with R. (Boophilus) decoloratus ticks, while on average 30% of the cattle in Bunghaji, Hitunga and Magoje were inconsistently infested. Seroconversion rates of cattle to Anaplasma marginale infection under low tick challenge were higher than those under high tick challenge, but the reverse was true for Babesia bigemina infection. For Theileria parva infection, seroconversion rates of cattle older than 6 months under low tick challenge were significantly higher than those under high tick challenge (P < 0.05). However, the likelihood of occurrence of theileriosis cases among calves (0-6 m) under high tick challenge was 6 times (Odds ratio = 5.82 [1.30-36.37]) higher than under low tick challenge. The high density of anti-tick plants Lantana camara and Ocimum suave that were widespread in villages with low tick challenge, among other factors, was probably the cause for unfavourable tick survival.

Population-dynamics focussed rapid rural mapping and characterisation of the peri-urban interface of Kampala, Uganda.

In developing countries, cities are rapidly expanding and urban and peri-urban agriculture (UPA) has an important role in feeding these growing urban populations; however such agriculture also carries public health risks such as zoonotic disease transmission. It is important to assess the role of UPA in food security and public health risks to make evidence-based decisions on policies. Describing and mapping the peri-urban interface (PUI) are the essential first steps for such an assessment. Kampala, the capital city of Uganda is a rapidly expanding city where the PUI has not previously been mapped or properly described. In this paper we provide a spatial representation of the entire PUI of Kampala economic zone and determine the socio-economic factors related with peri-urbanicity using a population-dynamics focussed rapid rural mapping. This fills a technical gap of rapid rural mapping and offers a simple and rapid methodology for describing the PUI which can be applied in any city in developing countries for wide range of studies.

Controlling sleeping sickness - a review.

Following a period characterized by severe epidemics of sleeping sickness, restoration of effective control and surveillance systems has raised the question of eliminating the disease from sub-Saharan Africa. Given sufficient political and financial support, elimination is now considered a reasonable aim in countries reporting zero or less than 100 cases per year. This success may lead health authorities across the affected region to downgrade the disease from 'neglected' to simply being ignored. In view of the significant levels of under-reporting of sleeping sickness mortality in rural communities, this could be a short-sighted policy. Loss of capacity to deal with new epidemics, which can arise as a consequence of loss of commitment or civil upheaval, would have serious consequences. The present period should be seen as a clear opportunity for public-private partnerships to develop simpler and more cost-effective tools and strategies for sustainable sleeping sickness control and surveillance, including diagnostics, treatment and vector control.

Clinical features associated with seroconversion to Anaplasma marginale, Babesia bigemina and Theileria parva infections in African cattle under natural tick challenge.

A longitudinal study was conducted in Southeast Uganda for 14 months on 640 Zebu cattle kept under natural tick challenge, with a view to identifying clinical features for prediction of seroconversion to Anaplasma marginale, Babesia bigemina and Theileria parva infections. Physical examination, condition scoring and tick counts were undertaken on all cattle every 4 weeks. In addition, 5300 sera were collected and analysed for antibodies against A. marginale, B. bigemina and T. parva infections using the enzyme-linked immunosorbent assay (ELISA). The major clinical features compiled included weight loss, fever (rectal temperature), anaemia (packed cell volume), pallor of mucous membranes, lymph node enlargement, staring coat, diarrhoea and lacrymation. The risk factors included tick challenge at village level, sex, age, Rhipicephalus spp. density and Boophilus spp. density on individual animals. Using a binary logistic regression model, the clinical features and risk factors were analysed. The results suggest that increasing rectal temperature was associated with increased probability for seroconversion to A. marginale, while high level of Rhipicephalus spp. density and increasing packed cell volume (PCV) were significantly associated with reduced probability of seroconversion. Although statistically significant, none of the factors had large effects, with odds ratios (OR) of 0.87, 1.15 and 0.98 for Rhipicephalus spp. density, rectal temperature and PCV, respectively. For B. bigemina infection, a high level of Boophilus spp. density, anaemia and staring coat were significantly associated with increased probability of seroconversion (OR 1.50, 1.78, 1.37, respectively). Presence of lacrymation and old age were associated with reduced probability of seroconversion (OR 0.52, 0.86 respectively). For T. parva infection, lymph node enlargement (OR 1.30) was associated with increased probability of seroconversion, while high Rhipicephalus spp. density and increasing packed cell volume (PCV) were associated with reduced probability of seroconversion (OR 0.68 and 0.98, respectively). In conclusion, presence and intensity of the respective tick vectors for tick-borne diseases, age and clinical features such as anaemia, fever, staring coat, lymph node enlargement and lacrymation are indicators for seroconversion to A. marginale, B. bigemina and T. parva infections in cattle. These indicators for seroconversion could be exploited in the development of decision support tools for clinical diagnosis of tick-borne diseases.

Antioxidants promote establishment of trypanosome infections in tsetse.

Efficient, cyclical transmission of trypanosomes through tsetse flies is central to maintenance of human sleeping sickness and nagana across sub-Saharan Africa. Infection rates in tsetse are normally very low as most parasites ingested with the fly bloodmeal die in the fly gut, displaying the characteristics of apoptotic cells. Here we show that a range of antioxidants (glutathione, cysteine, N-acetyl-cysteine, ascorbic acid and uric acid), when added to the insect bloodmeal, can dramatically inhibit cell death of Trypanosoma brucei brucei in tsetse. Both L- and D-cysteine invoked similar effects suggesting that inhibition of trypanosome death is not dependent on protein synthesis. The present work suggests that antioxidants reduce the midgut environment protecting trypanosomes from cell death induced by reactive oxygen species.

Programmed cell death in African trypanosomes.

Until recently it had generally been assumed that apoptosis and other forms of programmed cell death evolved during evolution of the metazoans to regulate growth and development in these multicellular organisms. However, recent research is adding strength to the original phenotypic observations described almost a decade ago which indicated that some parasitic protozoa may have evolved a cell death pathway analogous to the process described as apoptosis in metazoa. Here we explore the implications of a programmed cell death pathway in the African tsetse-transmitted trypanosomes.

Glossina fuscipes fuscipes in the trypanosomiasis endemic areas of south eastern Uganda: apparent density, trypanosome infection rates and host feeding preferences.

A study was undertaken in three districts in south eastern Uganda endemic for human and animal trypanosomiasis, to investigate the status of the vector tsetse fly population. Apparent density (AD) of tsetse was between 2 and 21 flies/trap/day across the three districts, with Glossinia fuscipes fuscipes identified as the predominant species. Trypanosomes were observed in G.f. fuscipes with an infection rate, as determined by microscopy, of 1.55% across the three studied areas. However, trypanosome infections were only identified in female flies giving an infection rate of 2.39% for the female tsetse when this sex was considered in isolation; no male flies were found to be infected. Bloodmeal analysis highlighted 3 principal vertebrate hosts, namely cattle, pigs and monitor lizards (Varanus niloticus). The implication of this, in relation to the cycle of transmission for human infective trypanosomes between domestic animals and man, is discussed.

Human African trypanosomiasis: Epidemiology and control.

Human African trypanosomiasis (HAT), or sleeping sickness, describes not one but two discrete diseases: that caused by Trypanosoma brucei rhodesiense and that caused by T. b. gambiense. The Gambian form is currently a major public health problem over vast areas of central and western Africa, while the zoonotic, Rhodesian form continues to present a serious health risk in eastern and southern Africa. The two parasites cause distinct clinical manifestations, and there are significant differences in the epidemiology of the diseases caused. We discuss the differences between the diseases caused by the two parasites, with an emphasis on disease burden, reservoir hosts, transmission, diagnosis, treatment and control. We analyse how these differences impacted on historical disease control trends and how they can inform contemporary treatment and control options. We consider the optimal ways in which to devise HAT control policies in light of the differing biology and epidemiology of the parasites, and emphasise, in particular, the wider aspects of control policy, outlining the responsibilities of individuals, governments and international organisations in control programmes.

Central point sampling from cattle in livestock markets in areas of human sleeping sickness.

We present the results of a study to determine the value of central point sampling in cattle markets as a means of estimating the trypanosomiasis (T. brucei s.l.) prevalence in the surrounding landscape in Uganda. We find that in the epidemic area studied, central point sampling is a good predictor of prevalence in surrounding villages, but not in endemic areas. We also find that animals infected with trypanosomiasis are more likely to be brought for sale in livestock markets in endemic areas; we discuss these results in relation to the prevention of the spread of sleeping sickness.

Quantifying the level of under-detection of Trypanosoma brucei rhodesiense sleeping sickness cases.

To formally quantify the level of under-detection of Trypanosoma brucei rhodesiense sleeping sickness (SS) during an epidemic in Uganda, a decision tree (under-detection) model was developed; concurrently, to quantify the subset of undetected cases that sought health care but were not diagnosed, a deterministic (subset) model was developed. The values of the under-detection model parameters were estimated from previously published records of the duration of symptoms prior to presentation and the ratio of early to late stage cases in 760 SS patients presenting at LIRI hospital, Tororo, Uganda during the 1988--1990 epidemic of SS. For the observed early to late stage ratio of 0.47, we estimate that the proportion of under-detection in the catchment area of LIRI hospital was 0.39 (95% CI 0.37--0.41) i.e. 39% of cases are not reported. Based on this value, it is calculated that for every one reported death of SS, 12.0 (95% CI 11.0--13.0) deaths went undetected in the LIRI hospital catchment area - i.e. 92% of deaths are not reported. The deterministic (subset) model structured on the possible routes of a SS infection to either diagnosis or death through the health system or out of it, showed that of a total of 73 undetected deaths, 62 (CI 60-64) (85%) entered the healthcare system but were not diagnosed, and 11 (CI 11--12) died without seeking health care from a recognized health unit. The measure of early to late stage presentation provides a tractable measure to determine the level of rhodesiense SS under-detection and to gauge the effects of interventions aimed at increasing treatment coverage.

Aphid-symbiotic bacteria cultured in insect cell lines.

The cells and tissues of many aphids contain bacteria known as "secondary symbionts," which under specific environmental circumstances may be beneficial to the host insect. Such symbiotic bacteria are traditionally described as intractable to cultivation in vitro. Here we show that two types of aphid secondary symbionts, known informally as T type and U type, can be cultured and maintained in three insect cell lines. The identities of the cultured bacteria were confirmed by PCR with sequencing of 16S rRNA gene fragments and fluorescence in situ hybridization. In cell lines infected with bacteria derived from aphids harboring both T type and U type, the U type persisted, while the T type was lost. We suggest that the two bacteria persist in aphids because competition between them is limited by differences in tropism for insect tissues or cell types. The culture of these bacteria in insect cell lines provides a new and unique research opportunity, offering a source of unibacterial material for genomic studies and a model system to investigate the interactions between animal cells and bacteria. We propose the provisional taxon names "Candidatus Consessoris aphidicola" for T type and "Candidatus Adiaceo aphidicola" for U type.

A burgeoning epidemic of sleeping sickness in Uganda.

The epidemic of Trypanosoma brucei rhodesiense sleeping sickness in eastern Uganda, which began in 1998 as a result of movements of the livestock reservoir of the parasite, has continued to spread. An additional 133 000 people have been put at risk of infection in Kaberamaido, another newly affected district. The few resources committed to control interventions in Soroti district have failed to contain the epidemic. The high prevalence of the parasite in cattle presents a significant risk for transmission to human beings and further spread of this neglected zoonotic disease. Targeted interventions are urgently needed to control epidemics and reduce the high mortality resulting from sleeping sickness.