Vector-borne infections in the tropics and health policy issues in the twenty-first century

Evaluation of emerging infectious disease and the importance of SINAN for epidemiological surveillance of Venezuelans immigrants in Brazil

BACKGROUND

Following socio-economic turmoil in Venezuela, millions of the Venezuelan people are migrating to the neighboring Latin American countries including Brazil. Besides the social and economic burden of these migrants, Brazil must manage the health-related issues arising as consequence of these Venezuelan migrants. Poor health services in Venezuela along with unhygienic travelling conditions, lack of food (malnutrition) and potable water, unhealthy and overcrowded refugee camps or shelters, poor availability of medical services have made the migrant Venezuelan population susceptible to various diseases, especially infectious diseases. SINAN system is a health-related system in Brazil that keeps track of different health occurrences in the society and allows health care workers and policymakers free access to these data.

OBJECTIVES

To evaluate the emergence of infectious diseases as a consequence of the arrival of Venezuelans immigrants in Brazil and to assess the importance of SINAN for epidemiological surveillance.

METHODS

Observational retrospective study. Data were collected from the SINAN system between 2015 and 2017 and was analyzed using descriptive statistics, and Mann-Whitney test (using SPSS tool version 12). Evaluated infectious diseases in this study were tuberculosis, sexually transmitted infections (STIs), HIV/AIDS, syphilis, viral hepatitis, leishmaniasis, and malaria.

RESULTS

STIs were the most commonly reported diseases. Compared to Brazilians, Venezuelan migrants reported significantly higher number of HIV/Aids (p < 0.046) and leishmaniasis cases (p < 0.049), while Brazilians reported significantly higher number of hepatitis cases (p < 0.046). Malaria was also more prevalent among Venezuelan migrants than native Brazilians.

CONCLUSION

Increased incidence of infectious diseases among the migrant population should be considered seriously as lack of adequate control of these diseases might lead to outbreaks.

The cross-cutting contribution of the end of neglected tropical diseases to the sustainable development goals

The Sustainable Development Goals (SDGs) call for an integrated response, the kind that has defined Neglected Tropical Diseases (NTDs) efforts in the past decade.NTD interventions have the greatest relevance for SDG3, the health goal, where the focus on equity, and its commitment to reaching people in need of health services, wherever they may live and whatever their circumstances, is fundamentally aligned with the target of Universal Health Coverage. NTD interventions, however, also affect and are affected by many of the other development areas covered under the 2030 Agenda. Strategies such as mass drug administration or the programmatic integration of NTD and WASH activities (SDG6) are driven by effective global partnerships (SDG17). Intervention against the NTDs can also have an impact on poverty (SDG1) and hunger (SDG2), can improve education (SDG4), work and economic growth (SDG8), thereby reducing inequalities (SDG10). The community-led distribution of donated medicines to more than 1 billion people reinforces women's empowerment (SDG5), logistics infrastructure (SDG9) and non-discrimination against disability (SDG16). Interventions to curb mosquito-borne NTDs contribute to the goals of urban sustainability (SDG11) and resilience to climate change (SDG13), while the safe use of insecticides supports the goal of sustainable ecosystems (SDG15). Although indirectly, interventions to control water- and animal-related NTDs can facilitate the goals of small-scale fishing (SDG14) and sustainable hydroelectricity and biofuels (SDG7).NTDs proliferate in less developed areas in countries across the income spectrum, areas where large numbers of people have little or no access to adequate health care, clean water, sanitation, housing, education, transport and information. This scoping review assesses how in this context, ending the epidemic of the NTDs can impact and improve our prospects of attaining the SDGs.

Sensitivity of Anopheles gambiae population dynamics to meteo-hydrological variability: a mechanistic approach

BACKGROUND

Mechanistic models play an important role in many biological disciplines, and they can effectively contribute to evaluate the spatial-temporal evolution of mosquito populations, in the light of the increasing knowledge of the crucial driving role on vector dynamics played by meteo-climatic features as well as other physical-biological characteristics of the landscape.

METHODS

In malaria eco-epidemiology landscape components (atmosphere, water bodies, land use) interact with the epidemiological system (interacting populations of vector, human, and parasite). In the background of the eco-epidemiological approach, a mosquito population model is here proposed to evaluate the sensitivity of An. gambiae s.s. population to some peculiar thermal-pluviometric scenarios. The scenarios are obtained perturbing meteorological time series data referred to four Kenyan sites (Nairobi, Nyabondo, Kibwesi, and Malindi) representing four different eco-epidemiological settings.

RESULTS

Simulations highlight a strong dependence of mosquito population abundance on temperature variation with well-defined site-specific patterns. The upper extreme of thermal perturbation interval (+ 3°C) gives rise to an increase in adult population abundance at Nairobi (+111%) and Nyabondo (+61%), and a decrease at Kibwezi (-2%) and Malindi (-36%). At the lower extreme perturbation (-3°C) is observed a reduction in both immature and adult mosquito population in three sites (Nairobi -74%, Nyabondo -66%, Kibwezi -39%), and an increase in Malindi (+11%). A coherent non-linear pattern of population variation emerges. The maximum rate of variation is +30% population abundance for +1°C of temperature change, but also almost null and negative values are obtained. Mosquitoes are less sensitive to rainfall and both adults and immature populations display a positive quasi-linear response pattern to rainfall variation.

CONCLUSIONS

The non-linear temperature-dependent response is in agreement with the non-linear patterns of temperature-response of the basic bio-demographic processes. This non-linearity makes the hypothesized biological amplification of temperature effects valid only for a limited range of temperatures. As a consequence, no simple extrapolations can be done linking temperature rise with increase in mosquito distribution and abundance, and projections of An. gambiae s.s. populations should be produced only in the light of the local meteo-climatic features as well as other physical and biological characteristics of the landscape.

Community views on Cutaneous Leishmaniasis in Istalif, Afghanistan: implications for treatment and prevention

Afghanistan currently has the world's largest outbreak of Cutaneous Leishmaniasis with more than 9% of the population (270,000) of Kabul affected. Transmitted through the bite of a sandfly, this disfiguring skin disease causes ulcerous lesions and permanent scarring. Physical, social, and economic consequences of the disease among those affected, their families, and communities are severe. Current control programs consist of both treatment and prevention. A clear understanding of the underlying factors influencing people's treatment-seeking behavior and utilization of prevention methods is critical for program success. However, these factors have not been well established. This article investigates illness recognition and treatment-seeking behavior, beliefs about etiology and transmission of the disease, and views of prevention and protection among the population of Istalif, a district in theKabul Province. The knowledge, attitudes, and preferences of participants in the focus groups highlight barriers to current control efforts, as well as opportunities for behavior change. An intervention strategy is proposed based on the analysis of these factors and includes an attack phase of treatment to reduce the infective human reservoir, lower morbidity, and distribution of Long-Lasting Insecticide Nets to interrupt the transmission cycle. This is followed by a maintenance phase of treatment, vector control, individual protection, health education, promotion, and community mobilization.

Global factors driving emerging infectious diseases

The extinction of species across the globe is accelerating directly or indirectly from human activities. Biological impoverishment, habitat fragmentation, climate change, increasing toxification, and the rapid global movement of people and other living organisms have worked synergistically to diminish ecosystem function. This has resulted in unprecedented levels of disease emergence driven by human-induced environmental degradation, which poses a threat to the survival and health of biodiversity. What is often overlooked in the discussion of the health consequences to humans is that critically endangered wildlife species are at grave risk of extinction by disease outbreaks. As habitat becomes more compressed and with migration routes cut off, gene pools of small species are stranded in isolated habitat fragments. Species now are vulnerable to encroachment, malnutrition, environmental pollutants, and epidemics from domestic animals and humans. Furthermore, the continuous degradation of ecosystems is leading to increased stress, immunosuppression, and greater susceptibility to disease. Disease can be catastrophic to a diminished stressed population, becoming in some instances the leading factor of local, regional, and global extinctions. The strategies of the new field of conservation medicine include long-term monitoring, health assessment, and interventions to protect species at risk. We particularly must minimize the threat of any potentially catastrophic disease outbreaks resulting from anthropogenic changes to the environment. Current and future diagnostic molecular techniques offer new opportunities to identify tools for the management and possible treatment of diseases in imperiled species.

Diagnostic tools for filariasis elimination programs

The ambitious and exciting Global Programme to Eliminate Lymphatic Filariasis (GPELF) is largely based on a strategy of mass drug administration (MDA) of repeated rounds of antifilarial medications to endemic populations around the world. Diagnostic tools are important to GPELF because they affect decisions regarding where to distribute MDA, how to measure its effects, how to define targets and endpoints for stopping MDA, and how to monitor populations for possible resurgence of filariasis transmission following suspension of MDA. This article reviews available diagnostic tests for filariasis and their potential use as tools for different phases of filariasis elimination programs.

Infectious Disease in the Age of Globalization

This chapter explores the links between globalization and infectious diseases in relation to changes in four major spheres—economic, environmental, political and demographic, and technological. It highlights areas where the evidence suggests that processes of globalization have led to changes in the distribution, transmission rate, and, in some cases, management of infectious diseases.

Are New World leishmaniases becoming anthroponoses?

In the New World, leishmaniases are originally wild exoanthropic zoonoses developing in sylvatic ecotopes. For a long time, Leishmania parasites have shown a remarkable plasticity to face modifications in their environment. Now, both geographical extension and numerical increase of leishmaniasis cases in the New World are giving cause for concern. These circumstances might have been provoked by the simple invasion of zoonotic foci by humans. However, dramatic evolutionary mechanisms are also at work in the New World: (i) the reduction of biodiversity associated with anthropogenic environmental changes (deforestation and urbanization); and (ii) the subsequent adaptations and interactions of new vectors and reservoir hosts at the interface with humans. This paper considers that these processes could result in new pathogenic complexes tending to synanthropic zoonoses, if not anthroponoses. Increasing man-made risk factors could thus possibly make leishmaniases a growing public health concern in the New World.

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.

Drivers for the emergence and re-emergence of vector-borne protozoal and bacterial diseases

In recent years, vector-borne parasitic and bacterial diseases have emerged or re-emerged in many geographical regions causing global health and economic problems that involve humans, livestock, companion animals and wild life. The ecology and epidemiology of vector-borne diseases are affected by the interrelations between three major factors comprising the pathogen, the host (human, animal or vector) and the environment. Important drivers for the emergence and spread of vector-borne parasites include habitat changes, alterations in water storage and irrigation habits, atmospheric and climate changes, immunosuppression by HIV, pollution, development of insecticide and drug resistance, globalization and the significant increase in international trade, tourism and travel. War and civil unrest, and governmental or global management failure are also major contributors to the spread of infectious diseases. The improvement of epidemic understanding and planning together with the development of new diagnostic molecular techniques in the last few decades have allowed researchers to better diagnose and trace pathogens, their origin and routes of infection, and to develop preventive public health and intervention programs. Health care workers, physicians, veterinarians and biosecurity officers should play a key role in future prevention of vector-borne diseases. A coordinated global approach for the prevention of vector-borne diseases should be implemented by international organizations and governmental agencies in collaboration with research institutions.

The utility of geographic information systems (GIS) in rapid epidemiological assessments following weather-related disasters: methodological issues based on the Tropical Storm Allison Experience

Flooding is the most common natural disaster worldwide, and is the leading cause of weather-related deaths in the United States. Tropical storm Allison hit landfall near Galveston, Texas on June 5, 2001, causing the most severe flood-related damage ever recorded in the Houston metropolitan area. This devastating storm dumped 37 in of rain in 24h on parts of the city, killing 22 people and causing more than $5 billion in damage. The main goal of the public health response to tropical storm Allison was to rapidly evaluate the immediate health needs of the community. Geographical information system (GIS) technology was instrumental to the timeliness of this effort. We conducted a rapid needs assessment in the areas most affected by flooding using modified cluster sampling facilitated by GIS methodology. Of the 420 households participating in the survey, we found a significant increase in illness (OR, 5.1; 95% CI, 2.7-9.4), injuries (OR, 4.8; 95% CI, 1.9-12.8), and immediate health needs (OR, 3.3; 95% CI, 1.7-6.1) among persons living in flooded homes compared to non-flooded homes. There were 60 households reporting serious damage, 24 of which were outside the 500-year flood plain. We also obtained reliable estimates of the extent of damage and household needs to help guide relief efforts. These findings underscore the usefulness of rapid needs assessment as a tool to identify actual health threats and to facilitate delivery of resources to those with the greatest and most immediate need. Our ability to swiftly plan and implement a rapid needs assessment over a large geographical region within 1 week following the damage would not have been possible without the utilization of GIS methodology and the availability of skilled personnel and timely data resources.

Dealing with Global Infectious Disease Emergencies

The microbes that cause human infectious diseases are complex, dynamic, and constantly evolving. They reproduce rapidly, mutate frequently, adapt with relative ease to new environments and hosts, and frequently breach the species barrier between animals and humans. Social, economic, and environmental factors linked to a host of human populations and activities can accelerate and amplify these natural phenomena. The ability of infectious diseases to spread internationally—carried by humans, insect vectors, food and food products, and livestock—has been greatly augmented by the pressures of a crowded, closely interconnected, and highly mobile world. When they spread internationally, infectious diseases often lead to global emergencies.

Common themes in changing vector-borne disease scenarios

The impact of climate change on disease patterns is controversial. However, global burden of disease studies suggest that infectious diseases will contribute a proportionately smaller burden of disease over the next 2 decades as non-communicable diseases emerge as public health problems. However, infectious diseases contribute proportionately more in the poorest quintile of the population. Notwithstanding the different views of the impact of global warming on vector-borne infections this paper reviews the conditions which drive the changing epidemiology of these infections and suggests that such change is linked by common themes including interactions of generalist vectors and reservoir hosts at interfaces with humans, reduced biodiversity associated with anthropogenic environmental changes, increases in Plasmodium falciparum: P. vivax ratios and well-described land use changes such as hydrological, urbanization, agricultural, mining and forest-associated impacts (extractive activities, road building, deforestation and migration) which are seen on a global scale.

Challenges in using geographic information systems (GIS) to understand and control malaria in Indonesia

Malaria is a mosquito-borne disease of global concern with 1.5 to 2.7 million people dying each year and many more suffering from it. In Indonesia, malaria is a major public health issue with around six million clinical cases and 700 deaths each year. Malaria is most prevalent in the developing countries of the world. Aid agencies have provided financial and technical assistance to malaria-prone countries in an effort to battle the disease. Over the past decade, the focus of some of this assistance has been in the provision of geographic information systems (GIS) hardware, software and training. In theory, GIS can be a very effective tool in combating malaria, however, in practice there have been a host of challenges to its successful use.This review is based, in part, on the literature but also on our experience working with the Indonesian Ministry of Health. The review identifies three broad problem areas. The first of these relates to data concerns. Without adequate data, GIS is not very useful. Specific problem areas include: accurate data on the disease and how it is reported; basic environmental data on vegetation, land uses, topography, rainfall, etc.; and demographic data on the movement of people. The second problem area involves technology - specifically computer hardware, GIS software and training. The third problem area concerns methods - assuming the previous data and technological problems have been resolved - how can GIS be used to improve our understanding of malaria? One of the main methodological tools is spatial statistical analysis, however, this is a newly developing field, is not easy to understand and suffers from the fact that there is no agreement on standard methods of analysis.The paper concludes with a discussion of strategies that can be used to overcome some of these problems. One of these strategies involves using ArcView GIS software in combination with ArcExplorer (a public domain program that can read ArcView files) to deal with the problem of needing multiple copies of GIS software. Another strategy involves the development of a self-paced training package that can be used to train individuals

Challenges in using geographic information systems (GIS) to understand and control malaria in Indonesia

Malaria is a mosquito-borne disease of global concern with 1.5 to 2.7 million people dying each year and many more suffering from it. In Indonesia, malaria is a major public health issue with around six million clinical cases and 700 deaths each year. Malaria is most prevalent in the developing countries of the world. Aid agencies have provided financial and technical assistance to malaria-prone countries in an effort to battle the disease. Over the past decade, the focus of some of this assistance has been in the provision of geographic information systems (GIS) hardware, software and training. In theory, GIS can be a very effective tool in combating malaria, however, in practice there have been a host of challenges to its successful use.

This review is based, in part, on the literature but also on our experience working with the Indonesian Ministry of Health. The review identifies three broad problem areas. The first of these relates to data concerns. Without adequate data, GIS is not very useful. Specific problem areas include: accurate data on the disease and how it is reported; basic environmental data on vegetation, land uses, topography, rainfall, etc.; and demographic data on the movement of people. The second problem area involves technology – specifically computer hardware, GIS software and training. The third problem area concerns methods – assuming the previous data and technological problems have been resolved – how can GIS be used to improve our understanding of malaria? One of the main methodological tools is spatial statistical analysis, however, this is a newly developing field, is not easy to understand and suffers from the fact that there is no agreement on standard methods of analysis.

The paper concludes with a discussion of strategies that can be used to overcome some of these problems. One of these strategies involves using ArcView GIS software in combination with ArcExplorer (a public domain program that can read ArcView files) to deal with the problem of needing multiple copies of GIS software. Another strategy involves the development of a self-paced training package that can be used to train individuals

[Cooperation between an NGO and "host" states in the control of leprosy in Latin America]

The proliferation of nongovernmental organizations (NGOs) can be considered the result of the inability of the current democratic system to perform all the tasks desired by its citizens. Although NGOs often do quite positive work, they tend to diminish governmental power and are capable of interfering in the internal affairs of other countries. In this context, there are efforts to control their activities, and this control can produce both negative effects (blocking the defense of human rights) and positive ones (correcting the lack of coordination in the work by NGOs). NGOs working with the control of leprosy have a long history of cooperation with "host" states in Latin America. In the worst cases they work in a vacuum left by the state. In a country like Brazil, where the government prioritizes the control of Hansen disease and community participation in the political process - NGOs generally work "in harmony" with national authorities. The most useful contribution to state efforts has been the technical and financial support for training health personnel, supervision, and awareness-raising campaigns. Thus, the NGO becomes "quasi-governmental" in performing its tasks.

Lessons learned from the emergence of a new Trypanosoma brucei rhodesiense sleeping sickness focus in Uganda

During the latter months of 1998, cases of sleeping sickness caused by Trypanosoma brucei rhodesiense presented in Soroti district, eastern Uganda, a region which had not previously experienced cases of the disease. Cattle are the main reservoir for T b rhodesiense, by contrast with sleeping sickness caused by Trypanosoma brucei gambiense in west Africa where there appears to be no epidemiologically significant animal reservoir. Several factors have been identified that interacted to produce ideal conditions for the establishment of a new disease focus. After a period of civil unrest, Soroti, which is within the tsetse belt, was repopulated by people and later, cattle. Both the cattle restocking and the subsequent trade in these cattle at a local cattle market had a role in the appearance of the disease. Recently, molecular biology techniques have become available for the detection and genotype identification of T b rhodesiense and thus it is now possible to distinguish human infective and non-infective trypanosomes in cattle. In light of these advances in identification and in both field and epidemiological techniques, successful disease control management has become an achievable goal and will require the collaboration and expertise of clinicians, veterinarians, epidemiologists and laboratory scientists.

Hot spots in a wired world: WHO surveillance of emerging and re-emerging infectious diseases

The resurgence of the microbial threat, rooted in several recent trends, has increased the vulnerability of all nations to the risk of infectious diseases, whether newly emerging, well-established, or deliberately caused. Infectious disease intelligence, gleaned through sensitive surveillance, is the best defence. The epidemiological and laboratory techniques needed to detect, investigate, and contain a deliberate outbreak are the same as those used for natural outbreaks. In April 2000, WHO formalised an infrastructure (the Global Outbreak Alert and Response Network) for responding to the heightened need for early awareness of outbreaks and preparedness to respond. The Network, which unites 110 existing networks, is supported by several new mechanisms and a computer-driven tool for real time gathering of disease intelligence. The procedure for outbreak alert and response has four phases: systematic detection, outbreak verification, real time alerts, and rapid response. For response, the framework uses different strategies for combating known risks and unexpected events, and for improving both global and national preparedness. New forces at work in an electronically interconnected world are beginning to break down the traditional reluctance of countries to report outbreaks due to fear of the negative impact on trade and tourism. About 65% of the world's first news about infectious disease events now comes from informal sources, including press reports and the internet.