Infections in the Tropics – Where are we Stuck?

Tropical infections pose a vexed problem to humanity. Not only do these contribute to significant morbidity and mortality, but they also cause outbreaks, epidemics and pandemics. Further, they pose diagnostic dilemmas and management challenges. Infections are varied and aplenty in the tropics, ranging from bacterial, viral to fungal and protozoal. A whole lot of respiratory, gastrointestinal, neurotropic infections exist, but infections may also vary according to the topography, with some being endemic in peculiar areas, such as Japanese encephalitis or Kyasanur Forest Disease. Besides, commonly encountered infections which may present as acute undifferentiated febrile illness or at times, may present with multisystem manifestations, include malaria, dengue, chikungunya, enteric fever, leptospirosis, scrub typhus, and brucellosis. Tuberculosis (TB) is also an important infection in the tropics, which needs to be considered in the differential of a chronic febrile illness and at times, as differential of partially treated acute illnesses. All these infections, labeled generically as “infections in the tropics” or “tropical infections” have persisted through the centuries, and in fact of late posing greater threats and challenges. These diseases have not been restricted to the tropics alone, but have spread across borders due to increased migration, air travel, tourism, and work-related visits. Tackling the current scenario is crucial to prevent infections of the tropics turning ubiquitous. In the realm of tropical infections, humanity is primarily “stuck” due to persistent socioeconomic challenges, the impact of adverse climate change, emerging antimicrobial resistance (AMR), and systemic failures in public health initiatives (infrastructure and funding). The main hurdles can be stated as following: Socioeconomic factors: Many tropical regions coincide with low-development-index countries, which often have limited resources, poor sanitation, overcrowding, and inadequate healthcare facilities. These conditions are ideal for the proliferation of pathogens and their vectors, making it difficult to implement basic prevention and control measures effectively. TB is one such disease where overcrowding crucially dictates the number of people who can be infected and probably develop the disease when their immunity declines. In fact, many tropical diseases, such as cholera, typhoid, and helminthic infections, are primarily governed by the level of sanitation in the community Climate change: Warmer temperatures and changing weather patterns, such as extended rainy seasons, expand the geographical range and breeding grounds of disease vectors, such as Aedes and Anopheles mosquitoes. This has led to the re-emergence and rapid spread of diseases such as dengue fever and malaria into new areas, including parts of the US and Europe. Hot and humid conditions have always favoured the growth of various pathogens, and now, global warming has worsened the scenario. This has led to even more frequent outbreaks of various infectious diseases like periodic Nipah in Kerala, Ebola in Africa, prolonged annual persistence of dengue and malaria, among other illnesses Neglect and underfunding: A large group of diseases, known as neglected tropical diseases (NTDs), affects more than 1.4 billion people but remains consistently underfunded and underprioritized compared to diseases such as human immunodeficiency virus (HIV)/acquired immune deficiency syndrome, TB, and malaria (the “big three”). This lack of attention means research and development for better diagnostics, treatments, and vaccines often lag. For example, India is one of the major countries carrying the world’s filariasis burden, mostly spread across the western and eastern coastal borders. Yet, just recently, the national programme has been intensified in 2024 for its elimination via mass drug administration (MDA). Many such diseases, such as helminthic infections, cholera, dengue and other viral pathogens need to be prioritized with preventive and therapeutic measures at the forefront AMR: The misuse of broad-spectrum antimicrobials, low-potency antibiotic formulations, and the lack of reliable diagnostics in many affected regions contribute to a growing crisis of AMR. This makes common bacterial infections in the tropics much harder to treat. Typhoid and tuberculosis (TB) are some of the most common diseases to have faced the brunt of this entity, rendering them multidrug resistant and thus, even more difficult to manage. The over-the-counter drug sales and lack of more accurate yet cheaper diagnostic modalities are some of the factors to be blamed here Diagnostic challenges: Many tropical infections present with nonspecific, overlapping, vague symptoms, making them difficult to diagnose quickly and accurately. Misdiagnosis can lead to delayed treatment and worse outcomes. The Indian context encloses factors such as resource-limited settings, expensive and complex gold standard tests like polymerase chain reaction, lack of sensitive and specific tools for available tests, and a persistent data gap, making the management even tougher Inadequate infrastructure: A systematic and resilient process to curtail the spread of infection is as important as its management. Challenges in hospital design (e.g., lack of dedicated Airborne Infection Isolation rooms with negative-pressure ventilation for airborne diseases like TB), poor waste disposal, and unsafe injection practices hinder effective infection control efforts in healthcare settings. There are several areas wherein the progress in curtailing tropical infections seems to be dredging at a slow pace. Thes include: Weak surveillance and data deficits: There is a lack of robust, real-time, case-based disease surveillance systems across all states, making it difficult to assess the true burden of diseases such as scrub typhus and leptospirosis, or to identify and respond to outbreaks quickly. Many diseases are underreported due to a lack of definitive reporting systems, interstate variations, and a lack of implementation. The integrated disease surveillance program in India is trying to have a robust system in place, stressing upon daily reporting and trying to predict outbreaks timely and contain the same Inadequate water, sanitation, and hygiene: Many pathogens thrive in environments with poor sanitation and limited access to clean water. Despite campaigns like the Swachh Bharat Abhiyan, ensuring universal access to safe water and adequate sanitation remains a persistent challenge, contributing to recurrent outbreaks of waterborne diseases such as cholera and hepatitis (A and E). Every once in a while, the news of people getting ill due to contaminated drinking water resurfaces, just highlighting the grievances of the common man and the need to meet basic human rights in a developing country like India Resource constraints and political will – NTDs often receive limited funding and political attention compared to diseases such as HIV, TB, and malaria, as they primarily affect the poorest populations. This leads to shortages of dedicated personnel, diagnostic facilities, and essential medicines in endemic areas. Another hidden reason is the lack of financial incentives for pharmaceutical companies to invest in research and development for these NTDs in such a poorer population Lack of integrated approach: Control efforts often operate in isolated, disease-specific “vertical programs” rather than a coordinated, integrated public health system that addresses multiple diseases and their common underlying determinants (e.g., poverty, environment) simultaneously Limited awareness and aid access – alhough India has progressed towards being the 4th largest economy in the world, a significant fraction of the population still struggles, and is usually burdened with superstitions and is bound by societal norms, especially when it comes to health. The health facts have not yet found their way to various nooks and corners of this country. This is true for many tropical countries. Limited access to proper diagnosis and treatment, especially in rural areas, leads to delayed management and hence complicated presentation of these patients to the point where the damage usually becomes irreversible. What follows are severe illnesses with multiorgan failures and higher mortality, which are quite commonly witnessed in the tertiary medical centers. THE PATH FORWARD Addressing these persistent issues requires a holistic approach that includes strong institutional commitment, local research, and global collaboration. Key strategies involve: Developing and deploying new tools such as effective vaccines and novel vector control methods (e.g., genetically modified mosquitoes) Strengthening health systems and implementing basic, cost-effective infection control measures Addressing the root causes of poverty and improving sanitation and water sources Ensuring ongoing focus and funding for NTDs through initiatives like the WHO’s 2030 road map for NTDs. Various national programmes are already in place; what is required is the zeal for intensive preventive and therapeutic implementation measures through them. The National Vector Borne Disease Control Programme has adapted multisectoral integration, aiming to tackle the infections at all levels possible like, by vector control, vaccine development, new drug development and its accessibility. The malaria guideline aims at achieving zero indigenous malaria cases by 2027 and sustaining elimination by 2030. Under National Tuberculosis Elimination Programme (NTEP), 80% reduction in incidence and 90% reduction in mortality because of TB were targeted by 2025. Through better administrative support and better access to health-related knowledge, goals can be achieved. Syndromic surveillance has been ongoing in India, which covers acute febrile illnesses and severe acute respiratory illnesses, but most people consider the data to be just a tip of the iceberg, and hence, mandatory reporting must be emphasized for closer reflection of actual numbers. A crucial factor hindering growth is in the form of AMR. The National Action Plan for Antimicrobial Resistance follows “one health” strategy, which considers that human, animal, plant, and environment health are all interconnected. Keeping the above strategy, the policy makers have laid down various guidelines which have brought a few changes, like a ban on various fixed drug formulations, advice against the use of colistin in animals, etc. It also regularly emphasizes the need on following antibiotic stewardship program at all healthcare levels and timely vaccination. This is just a small step forward against this dreadful situation. The health community needs to understand the reality and come together to deal with it. India continues to face significant challenges in controlling tropical infections due to several factors, as discussed. While the country has made progress in eliminating some specific diseases, systemic issues remain a major hurdle in tackling the overall burden. Despite these challenges, India has achieved notable successes, like, we overcame the problem of leprosy being a health problem in the year 2005, which was a historical win against a tropical infection as well as social discrimination that came along. India has also successfully eliminated guinea worm disease (2000) and yaws (2016), and now the country is on the verge of eliminating visceral leishmaniasis (kala-azar) as a public health problem in most endemic areas. The case fatality rates have dropped for Japanese encephalitis, from 17.6% in 2014 to 7.1% in 2024. The country has achieved a reduction of 78.1% in Malaria morbidity and 77.6% in Malaria mortality between 2015 and 2024.[1] The MDA for filarial eradication is also underway, aiming for elimination by 2027 by achieving a high compliance (>90%).[2] However, sustaining this progress and applying lessons learned to other diseases requires a comprehensive and sustained systemic approach. The system must adapt and evolve. Technology-driven holistic development and implementation of strategies while simultaneously and progressively working toward the root cause is the way forward in dealing with tropical infections. Financial support and sponsorship None. Conflicts of interest There are no conflicts of interest.