Rabies is one of the oldest and deadliest zoonotic diseases , killing thousands of people worldwide each year. Rabies is due to viral infection typically transmitted to people via bites from infected animals, especially bats, carnivores, or domestic mammals. The dis ease has no cure other than vaccination. Because of aggressive vaccination programs for pets, most rabies cases in developed countries are transmitted from wildlife species. However, most rabies in developing countries is canine related, notably stray dogs. The difference between a developed nation and developing nation is how the resources (however small) are managed. Some of the offices in developing countries are occupied by people with no interest in caring the public. The characteristic feature of cities in developing nations is poor urban management. One could observe poor waste management practices—with unmoved garbage at every intersection, stray dogs and cattle sharing the road, open and overflowing drains and sewage, and stagnant water bodies which provide breeding grounds for insects. These unhygienic conditions in cities are favorable grounds for a plethora of infectious diseases. The first line of defense against rabies is controlling the stray dog population. Development of cheaper rabies vaccines for developing countries could lead to better immunization programs in humans and stray animals.

Leptospirosis, a disease caused by the bacteria Leptospira , is an emerging public health problem in urban centers of developing countries. The disease is transmitted through infected rodents [ 1 ]. 200 serotypes of Leptospira have been described [ 2 ]. Though vaccines to leptospirosis are available the efficacy is very limited because they usually only protect well against a single serovar. Hence there is a need to develop highly effective vaccines for this disease which could protect against multiple strains of this pathogen .

Other diseases of note that arise from mismanaged urban centers include mosquito-transmitted diseases including malaria, dengue fever [ 3 ], and chikungunya [ 4 ], and the rodent-transmitted plague . Crowded living conditions and refuse-contaminated flood waters around the shanty towns of Surat, India, provided a breeding ground for rats and infected fleas which were responsible for the 1994 plague caused by the bacteria Yersinia pestis [5 ]. Though targeted vector management can make a difference in terms of reducing vector abundance, once the disease is out of control vaccination is the only strategy to prevent collateral damage to a population. Currently there are no effective vaccines for malaria, dengue, chikungunya, etc. Vaccinologists should also look out for mutant strains during an epidemic outbreak so as to develop improved and effective vaccines.

References
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[1]. Levett PN (2001) Leptospirosis. Clin Microbiol Rev 14:296–326

[2]. Wang Z, Jin L, Wegrzyn A (2007) Leptospirosis vaccines. Microb Cell Fact 6:39

[3]. Quintero J, Brochero H, Manrique-Saide P, Barrera-Pérez M et al (2014) Ecological, bio logical and social dimensions of dengue vector breeding in five urban settings of Latin America: a multi-country study. BMC Infect Dis 14:38

[4]. Nagpal BN, Saxena R, Srivastava A, Singh N, Ghosh SK et al (2012) Retrospective study of chikungunya outbreak in urban areas of India. Indian J Med Res 135:351–358

[5]. Clem A, Galwankar S (2005) Plague: a decade since the 1994 outbreaks in India. J Assoc Physicians India 53:457–464