The burden of drug resistant tuberculosis in a predominantly nomadic population in Uganda: a mixed methods study

Background

Emergence of drug resistant tuberculosis (DR-TB) has aggravated the tuberculosis (TB) public health burden worldwide and especially in low income settings. We present findings from a predominantly nomadic population in Karamoja, Uganda with a high-TB burden (3500 new cases annually) and sought to determine the prevalence, patterns, factors associated with DR-TB.

Methods

We used mixed methods of data collection. We enrolled 6890 participants who were treated for tuberculosis in a programmatic setting between January 2015 and April 2018. A cross sectional study and a matched case control study with conditional logistic regression and robust standard errors respectively were used to the determine prevalence and factors associated with DR-TB. The qualitative methods included focus group discussions, in-depth interviews and key informant interviews.

Results

The overall prevalence of DR-TB was 41/6890 (0.6%) with 4/64,197 (0.1%) among the new and 37/2693 (1.4%) among the previously treated TB patients respectively. The drug resistance patterns observed in the region were mainly rifampicin mono resistant (68.3%) and Multi Drug-Resistant Tuberculosis (31.7%). Factors independently associated with DR-TB were previous TB treatment, adjusted odds ratio (aOR) 13.070 (95%CI 1.552–110.135) and drug stock-outs aOR 0.027 (95%CI 0.002–0.364). The nomadic lifestyle, substance use, congested homesteads and poor health worker attitudes were a great challenge to effective treatment of TB.

Conclusion

Despite having the highest national TB incidence, Karamoja still has a low DR-TB prevalence. Previous TB treatment and drug stock outs were associated with DR-TB. Regular supply of anti TB medications and health education may help to stem the burden of TB disease in this nomadic population.

Genomic analysis of group B Streptococcus from milk demonstrates the need for improved biosecurity: a cross-sectional study of pastoralist camels in Kenya

BACKGROUND

Streptococcus agalactiae (Group B Streptococcus, (GBS)) is the leading cause of mastitis (inflammation of the mammary gland) among dairy camels in Sub-Saharan Africa, with negative implications for milk production and quality and animal welfare. Camel milk is often consumed raw and presence of GBS in milk may pose a public health threat. Little is known about the population structure or virulence factors of camel GBS. We investigated the molecular epidemiology of camel GBS and its implications for mastitis control and public health.

RESULTS

Using whole genome sequencing, we analysed 65 camel milk GBS isolates from 19 herds in Isiolo, Kenya. Six sequence types (STs) were identified, mostly belonging to previously described camel-specific STs. One isolate belonged to ST1, a predominantly human-associated lineage, possibly as a result of interspecies transmission. Most (54/65) isolates belonged to ST616, indicative of contagious transmission. Phylogenetic analysis of GBS core genomes showed similar levels of heterogeneity within- and between herds, suggesting ongoing between-herd transmission. The lactose operon, a marker of GBS adaptation to the mammary niche, was found in 75 % of the isolates, and tetracycline resistance gene tet(M) in all but two isolates. Only the ST1 isolate harboured virulence genes scpB and lmb, which are associated with human host adaptation.

CONCLUSIONS

GBS in milk from Kenyan camel herds largely belongs to ST616 and shows signatures of adaptation to the udder. The finding of similar levels of within- and between herd heterogeneity of GBS in camel herds, as well as potential human-camel transmission highlights the need for improved internal as well as external biosecurity to curb disease transmission and increase milk production.

Factors hindering health care delivery in nomadic communities: a cross-sectional study in Timbuktu, Mali

Background

In Mali, nomadic populations are spread over one third of the territory. Their lifestyle, characterized by constant mobility, excludes them from, or at best places them at the edge of, health delivery services. This study aimed to describe nomadic populations’ characteristics, determine their perception on the current health services, and identify issues associated with community-based health interventions.

Methods

To develop a better health policy and strategic approaches adapted to nomadic populations, we conducted a cross-sectional study in the region of Timbuktu to describe the difficulties in accessing health services. The study consisted in administering questionnaires to community members in the communes of Ber and Gossi, in the Timbuktu region, to understand their perceptions of health services delivery in their settings.

Results

We interviewed 520 individuals, all members of the nomadic communities of the two study communes. Their median age was 38 years old with extremes ranging from 18 to 86 years old. Their main activities were livestock breeding (27%), housekeeping (26.4%), local trading (11%), farming (6%) and artisans (5.5%). The average distance to the local health center was 40.94 km and 23.19 km respectively in Gossi and Ber. In terms of barriers to access to health care, participants complained mainly about the transportation options (79.4%), the quality of provided services (39.2%) and the high cost of available health services (35.7%). Additionally, more than a quarter of our participants stated that they would not allow themselves to be examined by a health care worker of the opposite gender.

Conclusion

This study shows that nomadic populations do not have access to community-based health interventions. A number of factors were revealed to be important barriers per these communities’ perception including the quality of services, poverty, lifestyle, gender and current health policy strategies in the region. To be successful, future interventions should take these factors into account by adapting policies and methods.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-10481-w.

Extreme mobility of the world's largest flying mammals creates key challenges for management and conservation

BACKGROUND

Effective conservation management of highly mobile species depends upon detailed knowledge of movements of individuals across their range; yet, data are rarely available at appropriate spatiotemporal scales. Flying-foxes (Pteropus spp.) are large bats that forage by night on floral resources and rest by day in arboreal roosts that may contain colonies of many thousands of individuals. They are the largest mammals capable of powered flight, and are highly mobile, which makes them key seed and pollen dispersers in forest ecosystems. However, their mobility also facilitates transmission of zoonotic diseases and brings them in conflict with humans, and so they require a precarious balancing of conservation and management concerns throughout their Old World range. Here, we analyze the Australia-wide movements of 201 satellite-tracked individuals, providing unprecedented detail on the inter-roost movements of three flying-fox species: Pteropus alecto, P. poliocephalus, and P. scapulatus across jurisdictions over up to 5 years.

RESULTS

Individuals were estimated to travel long distances annually among a network of 755 roosts (P. alecto, 1427-1887 km; P. poliocephalus, 2268-2564 km; and P. scapulatus, 3782-6073 km), but with little uniformity among their directions of travel. This indicates that flying-fox populations are composed of extremely mobile individuals that move nomadically and at species-specific rates. Individuals of all three species exhibited very low fidelity to roosts locally, resulting in very high estimated daily colony turnover rates (P. alecto, 11.9 ± 1.3%; P. poliocephalus, 17.5 ± 1.3%; and P. scapulatus, 36.4 ± 6.5%). This indicates that flying-fox roosts form nodes in a vast continental network of highly dynamic "staging posts" through which extremely mobile individuals travel far and wide across their species ranges.

CONCLUSIONS

The extreme inter-roost mobility reported here demonstrates the extent of the ecological linkages that nomadic flying-foxes provide across Australia's contemporary fragmented landscape, with profound implications for the ecosystem services and zoonotic dynamics of flying-fox populations. In addition, the extreme mobility means that impacts from local management actions can readily reverberate across jurisdictions throughout the species ranges; therefore, local management actions need to be assessed with reference to actions elsewhere and hence require national coordination. These findings underscore the need for sound understanding of animal movement dynamics to support evidence-based, transboundary conservation and management policy, tailored to the unique movement ecologies of species.

A Review of Zoonotic Pathogens of Dromedary Camels

Dromedary, or one-humped, camels Camelus dromedarius are an almost exclusively domesticated species that are common in arid areas as both beasts of burden and production animals for meat and milk. Currently, there are approximately 30 million dromedary camels, with highest numbers in Africa and the Middle East. The hardiness of camels in arid regions has made humans more dependent on them, especially as a stable protein source. Camels also carry and may transmit disease-causing agents to humans and other animals. The ability for camels to act as a point source or vector for disease is a concern due to increasing human demands for meat, lack of biosafety and biosecurity protocols in many regions, and a growth in the interface with wildlife as camel herds become sympatric with non-domestic species. We conducted a literature review of camel-borne zoonotic diseases and found that the majority of publications (65%) focused on Middle East respiratory syndrome (MERS), brucellosis, Echinococcus granulosus, and Rift Valley fever. The high fatality from MERS outbreaks during 2012-2016 elicited an immediate response from the research community as demonstrated by a surge of MERS-related publications. However, we contend that other camel-borne diseases such as Yersinia pestis, Coxiella burnetii, and Crimean-Congo hemorrhagic fever are just as important to include in surveillance efforts. Camel populations, particularly in sub-Saharan Africa, are increasing exponentially in response to prolonged droughts, and thus, the risk of zoonoses increases as well. In this review, we provide an overview of the major zoonotic diseases present in dromedary camels, their risk to humans, and recommendations to minimize spillover events.

Understanding variation in migratory movements: A mechanistic approach

Spatial and temporal fluctuations in resource availability have led to the evolution of varied migration patterns. In order to appropriately time movements in relation to resources, environmental cues are used to provide proximate information for timing and the endocrine system serves to integrate these external cues and behavioral and physiological responses. Yet, the regulatory mechanisms underlying migratory timing have rarely been compared across a broad range of migratory patterns. First, we offer an updated nomenclature of migration using a mechanistic perspective to clarify terminology describing migratory types in relation to ecology, behavior and endocrinology. We divide migratory patterns into three types: obligate, nomadic, and fugitive. Obligate migration is characterized by regular and directed annual movements between locations, most commonly for breeding and overwintering, where resources are predictable and sufficient. Nomadic migrations occur less predictably than do obligate migrations as animals make use of potentially rich but ephemeral resources that occur unpredictably in space or time. Fugitive migrations move animals away from an area in response to severe disruption of environmental conditions and occur as part of an emergency life history stage. We also consider partially migratory populations, which include a mix of sedentary and migratory individuals; the movement patterns of partial migrants are expected to fall into one of the three types above. For these various forms of migration, we review our understanding of the environmental cues and endocrine mechanisms that underlie the expression of a migratory state. Several common hormonal mechanisms exist across the varied migratory forms, but there are also important areas where further investigations are needed in order to gain broad insight into the origin of movements and the diversity of migratory patterns. We propose that taking a comparative approach across the migratory types that considers endocrine mechanisms will advance a new understanding of migration biology.

Exploring the environmental drivers of waterfowl movement in arid landscapes using first-passage time analysis

BACKGROUND

The movement patterns of many southern African waterfowl are typified by nomadism, which is thought to be a response to unpredictable changes in resource distributions. Nomadism and the related movement choices that waterfowl make in arid environments are, however, poorly understood. Tracking multiple individuals across wide spatiotemporal gradients offers one approach to elucidating the cues and mechanisms underpinning movement decisions. We used first-passage time (FPT) to analyse high spatial and temporal resolution telemetry data for Red-billed Teal and Egyptian Geese across a 1500 km geographical gradient between 2008 and 2014. We tested the importance of several environmental variables in structuring movement patterns, focusing on two competing hypotheses: (1) whether movements are driven by resource conditions during the current period of habitat occupation (reactive movement hypothesis), or (2) whether movements are structured by shifts in the magnitude and direction of environmental variables at locations prior to occupation (prescient movement hypothesis).

RESULTS

An increase in rainfall at a 32 day lag (i.e., prior to wetland occupancy), along with tagging site, were significant predictors of FPT in both waterfowl species. There was a positive relationship between NDVI and FPT for Egyptian Geese during this 32 day period; the relationship was negative for Red-billed Teal. Consistent with findings for migratory grazing geese, Egyptian Geese prioritised food quality over food biomass. Red-billed Teal showed few immediate responses to wetland filling, contrary to what one would predict for a dabbling duck, suggesting high dietary flexibility. Our results were consistent with the prescient movement hypothesis.

CONCLUSIONS

Using FPT analysis we showed that the proximate drivers of southern African waterfowl movement are the dynamics of rainfall and primary productivity. Waterfowl appeared to be able to perceive and respond to temporal shifts in resource conditions prior to habitat patch occupation. This in turn suggests that their movements in semi-arid landscapes may be underpinned by intimate knowledge of the local environment; waterfowl pursue a complex behavioural strategy, locating suitable habitat patches proactively, rather than acting as passive respondents.

Sero-positivity and associated risk factors for contagious bovine pleuropneumonia under two cattle production systems in North Central Nigeria

A cross-sectional survey of 765 cattle in 125 nomadic and 375 cattle in 125 sedentary herds was conducted to investigate prevalence and risk factors for contagious bovine pleuropneumonia (CBPP) in the two production systems of Niger State in North Central Nigeria, between January and August 2013. Data on herd characteristics were collected using structured questionnaires administered on herd owners. Serological analysis was conducted using competitive enzyme linked immunosorbent assay (c-ELISA) test. Descriptive, univariate, and multivariate statistical analyses were conducted with OpenEpi version 2.3.1 software. Statistical significance was held at P < 0.05. CBPP sero-prevalence in nomadic cattle was 16.2 % (confidence interval (CI) 13.7-19.0) and 9.6 % (CI 6.9-12.9) in sedentary cattle. The overall cattle-level sero-prevalence for two the cattle production systems was 14.0 % (CI 12.1-16.1). Age and agro-ecological zones were significantly (P < 0.001 and P < 0.001, respectively) associated with sero-positivity to Mmm in nomadic production. Agro-ecological zone C had the highest sero-prevalence (25.3 %, CI 20.2-31.0). No significant cattle factors were detected in sedentary production. Factors significantly associated with CBPP occurrence at herd-level were contacts with other herds during grazing (P < 0.001) and at watering points (P < 0.001). Others were introduction of new cattle into herd (P < 0.001), outbreaks of CBPP in an area (P < 0.001), socio-cultural factors of cattle gifts and dowry payment (P < 0.001), herd composition of keeping cattle and small ruminants together (P < 0.001), and long trekking during migrations (P = 0.0009). This study had shown the burden of CBPP in the two production systems. Sero-diagnosis and risk factor identification should be institutionalized as elements of epidemio-surveillance and control strategies for CBPP, especially in resource-poor pastoralists' settlements in Nigeria.

Obligate versus rich patch opportunism: evolution and endocrine mechanisms

Opportunistic breeding has been hypothesized to evolve in response to rare or unpredictable resource pulses. In this traditional view of opportunism, individuals invest heavily in reproduction whenever conditions are permissive for breeding, perhaps at the expense of investment in survival. We term this strategy 'obligate opportunism' (OBO). We also present an additional strategy that could account for the evolution of opportunism. High mobility may allow individuals to move between rich patches of resources that are spatially or temporally unpredictable, reducing exposure to food scarcity and taking advantage of breeding opportunities. This strategy, which we term 'rich patch exploiter' (RPE), predicts that investment in survival-enhancing processes may occur at the expense of reproduction despite high resource availability. We review examples to determine which opportunists better match predictions from the OBO strategy or the RPE strategy and then review endocrine profiles in the context of the two strategies.