morbidity is in india and southeast asia. globally, there are an estimated 421,000 envenomings each year (about 1 in 4 snakebites) and 20,000 deaths, but snakebites often go unreported. this section is an excerpt from snakebite. a rattlesnake bite on the foot of a 9-year-old girl in venezuela a snakebite is an injury caused by the bite of a snake, especially a venomous snake. a common sign of a bite from a venomous snake is the presence of two puncture wounds from the animal's fangs. sometimes venom injection from the bite may occur. this may result in redness, swelling, and severe pain at the area, which may take up to an hour to appear. vomiting, blurred vision, tingling of the limbs, and sweating may result. most bites are on the hands, arms, or legs. fear following a bite is common with symptoms of a racing heart and feeling faint. the venom may cause bleeding, kidney failure, a severe allergic reaction, tissue death around the bite, or breathing problems. bites may result in the loss of a limb or other chronic problems or even death. effects for patients social stigma several ntds, such as leprosy, cause severe deformities that result in social stigma. stigma is considered to be the "hidden burden" of neglected tropical diseases and is not accounted for in measures such as disability-adjusted life years (dalys). other ntds that carry heavy social stigma include onchocerciasis, lymphatic filariasis, plague, buruli ulcer, leishmaniasis, and chagas disease. lymphatic filariasis, for example, causes severe deformities that can result in denial of marriage and inability to work. studies in ghana and sri lanka have demonstrated that support groups for patients with lymphatic filariasis can increase participants' self-esteem, quality of life, and social relations through social support and providing practical advice on how to manage their illness. the social effects of neglected tropical diseases have been shown to affect men and women in different ways. men are socially stigmatized in a way that detrimentally affects their economic prospects. women are more likely to be affected in the areas of marriage and family. mental health a 2012 review found that infection with a neglected tropical disease predisposes individuals to poor mental health. this is partially due to the social stigma that surrounds ntds, but is also likely caused by the subsequent lack of access to health and social services. overall, being a member of the infected community was found to cut individuals off from multiple aspects of society via civic rights, educational opportunities, and employment. a high prevalence of post-traumatic stress disorder (ptsd) and depression was found in those affected with snakebite survivors. there is a need for more research be directed to understanding the psychological aspects of neglected tropical diseases in order to fully untangle their co-effects and on how they can be dealt with better in health systems in countries where mental health professionals are scarce. gender ntds disproportionately affect women and children. there is also the added risk of hookworm infection during pregnancy and the potential to transfer diseases such as chagas during pregnancy. a study in uganda found that women were more easily able to obtain treatment because they had fewer occupational responsibilities than men and were more trusting of treatment, but ignorance of the effects of medicines on pregnant women prevented adequate care. the paper concludes that gender should be considered when designing treatment programs in uganda. additionally, women often bear a heavier social stigma in relation to the pressure to marry. economic effects the cost of treatment of some of these diseases, such as buruli ulcer, can amount to over twice the yearly income of an average household in the lowest income quartile, while for the highest income quartile, the burden is slightly less than the average household income. these enormous financial costs often cause deferral of treatment and financial ruin, but there is inequality between the wealthy and poor in terms of economic burden. these diseases also cost the government in terms of healthcare and lost worker productivity through morbidity and shortened life spans. in kenya, for example, deworming is estimated to increase average adult income by 40 percent, which is a benefit-to-cost ratio of 100. each untreated case of trachoma is estimated to cost us$118 in lost productivity. each case of schistosomiasis causes a loss of 45.4 days of work per year. most of the diseases cost the economies of various developing countries millions of dollars. large-scale prevention campaigns are predicted to increase agricultural output and education levels. the low cost of treatment for ntds can be attributed to the large scale of the programs, free provision of drugs by pharmaceutical companies, delivery modes of drugs, and the unpaid volunteers who distribute the drugs. the economic burden of ntds is undervalued and therefore the corresponding economic effect and cost-effectiveness of a decreased prevalence of ntds is underestimated. the investment return on measures to control neglected tropical diseases is estimated to be between 14 and 30 percent, depending on the disease and region. coinfection coinfection is a major concern with neglected tropical diseases, making ntds more damaging than their mortality rates might portray. because the factors that support neglected tropical diseases (poverty, inadequate healthcare, inadequate sanitation practices, etc.) support all ntds, they are often found in overlapping distributions. helminth infections, as the most common infection of humans, are often found to be in multi-infection systems. for example, in brazil, low socioeconomic status contributes to overcrowded housing. in these same areas, coinfection by necator americanus and schistosoma mansoni is common. the effect of each worm weakens the immune system of those infected, making infection from the other easier and more severe. for this reason, coinfection carries a higher risk of mortality. ntds may also play a role in infection with other diseases, such as malaria, hiv/aids, and tuberculosis. the ability of helminths to manipulate the immune system may create a physiological environment that could exacerbate the progression of hiv/aids. some evidence from senegal, malawi, and thailand has shown that helminth infections raise the risk of malarial infection. prevention, treatment and eradication eliminating ntds in côte d'ivoire through education and distribution of anti-parasitic drugs prevention and eradication are important because "of the appalling stigma, disfigurement, blindness and disabilities caused by ntds." the possibility of eliminating or eradicating dracunculiasis, leprosy, lymphatic filariasis, onchocerciasis, trachoma, sleeping sickness, visceral leishmaniasis, and canine rabies within the next ten years was the principal aim of the london declaration on neglected tropical diseases, which is a collaborative effort involving the who, the world bank, the bill & melinda gates foundation, the world's 13 leading pharmaceutical companies, and government representatives from the us, uk, united arab emirates, bangladesh, brazil, mozambique, and tanzania. it was launched in january 2012. while the current era has had a noticeable uptick in biological research into neglected tropical diseases, prevention may be supplemented by social and development outreach. spiegal and his coauthors advocated for this to take the form of "social offset". social offset entails the delegation of some of the funding for biotechnological research to social programs. the attempts to alleviate some of the surrounding factors (such as poverty, poor sanitation, overcrowding, poor healthcare, etc.) that greatly exacerbate the conditions brought on by neglected tropical diseases. projects such as these also strengthen the goal of sustained eliminations rather than quickly addressing symptoms. policy initiatives there are many prevention and eradication campaigns funded, for example, by the world health organization, us agency for international development, bill & melinda gates foundation, and uk department for international development. sustainable development goal 3 has this target to eradicate ntds: "by 2030, end the epidemics of aids, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases." who roadmap of 2012 in 2012, who published an ntd "roadmap", which contained milestones for 2015 and 2020 and specified targets for eradication, elimination, and intensified control of the different ntds. for example: ntds planned to be eradicated: dracunculiasis (by the year 2015), endemic treponematoses (yaws) (by 2020) ntds planned to be eliminated globally by 2020: blinding trachoma, leprosy, human african trypanosomiasis, and lymphatic filariasis ntds planned to be eliminated in certain regions: rabies (by 2015 in latin america, by 2020 in southeast asia and the western pacific), chagas disease (transmission through blood transfusion by 2015, intra-domiciliary transmission by 2020 in the americas), visceral leishmaniasis (by 2020 in the indian subcontinent), onchocerciasis (by 2015 in latin america), and schistosomiasis (by 2015 in the eastern mediterranean region, the caribbean, indonesia, and the mekong river basin, by 2020 in the americas and western pacific) ntds planned to be eliminated in certain countries: human african trypanosomiasis (by 2015 in 80 percent of areas in which it occurs), onchocerciasis (by 2015 in yemen, by 2020 in selected countries in africa), and schistosomiasis (by 2020 in selected countries in africa) intensified control with specific targets for 2015 and 2020 are provided for these ntds: dengue, buruli ulcer, cutaneous leishmaniasis, taeniasis/cysticercosis and echinococcosis/hydatidosis, foodborne trematode infections, and soil-transmitted helminthiases others the u.s. food and drug administration priority review voucher is an incentive for companies to invest in new drugs and vaccines for tropical diseases. a provision of the food and drug administration amendments act (hr 3580) awards a transferable "priority review voucher" to any company that obtains approval for a treatment for one of the listed diseases. the voucher can later be used to accelerate the review of an unrelated drug. this program is for all tropical diseases and includes medicines for malaria and tuberculosis. the first voucher given was for coartem, a malaria treatment. it does not use or define the term "neglected", though most of the diseases listed are often included on lists of neglected diseases. the prize was proposed by duke university faculty henry grabowski, jeffrey moe, and david ridley in their 2006 health affairs paper "developing drugs for developing countries". in 2007, united states senators sam brownback (r-ks) and sherrod brown (d-oh) sponsored an amendment to the food and drug administration amendments act of 2007. president george w. bush signed the bill in september 2007. deworming treatment further information: mass deworming deworming treatments in infected children may have some nutritional benefit, as worms are often partially responsible for malnutrition. however, in areas where these infections are common, there is strong evidence that mass deworming campaigns do not have a positive effect on children's average nutritional status, levels of blood haemoglobin, cognitive abilities, performance at school, or survival. to achieve health gains in the longer term, improvements in sanitation and hygiene behaviours are also required, together with deworming treatments. the effect of mass deworming on school attendance is disputed. it has been argued that mass deworming has a positive effect on school attendance. the long-term benefits of deworming include a decrease in school absenteeism by 25 percent and an increase in adult earnings by 20 percent. a systematic review, however, found that there is little or no difference in attendance in children who receive mass deworming compared to children who did not. one study found that boys were enrolled in primary school for more years than boys who were in schools that did not offer such programs. girls in the same study were about a quarter more likely to attend secondary school if they received treatment. both groups went on to participate in more skilled sectors of the labor market. the economic growth generated from school programs such as this may balance out the actual expenses of the program. however, the results of this study are disputed (i.a. due to a high risk of bias in the study), and the positive long-term outcomes of mass deworming remain unclear. integration of treatment school nurse checks student's health in kenya inclusion of ntds into initiatives for malaria, hiv/aids, and tuberculosis, as well as integration of ntd treatment programs, may have advantages given the strong link between these diseases and ntds. some neglected tropical diseases share common vectors (sandflies, black flies, and mosquitos). both medicinal and vector control efforts may be combined. a four-drug rapid-impact package has been proposed for widespread proliferation. administration may be made more efficient by targeting multiple diseases at once, rather than separating treatment and adding work to community workers. this package is estimated to cost us$0.40 per patient. when compared to stand-alone treatment, the