Introduction

Throughout human history, people have used various materials from nature to cure their illnesses and improve their health [1]. Traditional human populations have a broad natural pharmacopoeia consisting of wild plant and animal species. According to the World Health Organization, 80 percent of the developing world's rural population depends on traditional medicines for its primary healthcare needs [2]. In many parts of the world, traditional medicine is the preferred form of health care, and remains the most available and affordable form of therapy in low income countries [3]. Ingredients sourced from wild plants and animals are not only used in traditional medicines, but are also increasingly valued as raw materials in the preparation of modern medicines and herbal preparations. Nature has been the source of medicinal agents for thousands of years, and an impressive number of modern drugs have been isolated from natural sources, many based on their use in traditional medicine [1].

The use of biological resources for various therapies has been documented in many different parts of the world [4–16]. Plants and animals have been used as medicinal sources since ancient times [1, 2, 17–22], and even today animal and plant-based pharmacopeias continue to play an essential role in world health care [1, 2, 4]. Although plants and plant-derived materials make up the majority of ingredients used in most traditional medical systems globally, whole animals, animal parts, and animal-derived products (e.g., urine, fat, etc.) also constitute important elements of the Materia Medica [2, 23–25].

The use of organs or parts of animals as medicine is the basis of many traditional therapeutic practices [25]. Zootherapy is the treatment of human ailments with remedies made from animals and their products [2]. As Marques [26] states, "all human culture which presents a structured medical system will utilize animals as medicines". The phenomenon of zootherapy is marked both by a broad geographical distribution and very deep historical origins. In modern societies, zootherapy constitutes an important alternative among many other known therapies practiced worldwide [2, 27–39]. Despite its prevalence in traditional medical practices worldwide, research on this phenomenon has often been neglected in comparison to medicinal plant research [2]. Traditionally, medicinal animals have received little attention from ethnobiologists and anthropologists. It is only within the past few decades that researchers have begun to systematically investigate the uses of medicinal plants, and an awareness of the variety and importance of nonbotanical remedies (of animal and mineral origin) is emerging [40]. In spite of the recent surge in publications about zootherapeutics the subject is still far from being well covered, and even more distant from being exhausted. The lack of zootherapeutic studies in Latin America (and in the world in general) has contributed to an underestimation of the importance of zootherapeutic resources [41, 42].

Many cultures still employ traditional medicine that includes animal-derived remedies. Probably the most famous of these are the Chinese, who use animals for a variety of ailments. Lesser known and studied, though just as varied and rich is Latin America's long tradition of animal-remedies for all kinds of ailments. Latin America's rich biological and cultural diversity makes it an exceptional location in which to examine and increase our knowledge of faunistic resources used as in traditional folk medicine, to draw attention to their importance in public health, and protect traditional knowledge and biodiversity.

Latin America is outstanding both because of its great wealth of genetic resources and complex cultural diversity [43–46]. The adaptation of the various human groups to the region's rich biological resources generated invaluable local knowledge systems that include extensive information on plant and animal uses in general [43, 47–59]. In that context, the aim of this study was to provide an overview of the use of medicinal animals in Latin America, identify those species used as folk remedies, and discuss the implications of zootherapy for public health and biological conservation.

Methods

Study area

Latin America is a vast region spanning parts of North America, almost all of South America, and much of the West Indies. It encompasses 19 countries as well as Puerto Rico, a commonwealth territory of the United States, and, arguably, even parts of southwestern United States [46]. In Latin America and the Caribbean, the population stood at 577 million in 2008 and is projected to increase to 778 million by 2050 [60]. It is the most urbanized region in the developing world, with around three-quarters of the population living in urban areas [43]. The population of Latin America is a composite of ancestries, ethnic groups, and races, making the region one of the most--if not the most--racially and ethnically diverse in the world. The specific composition varies from country to country: Some countries have a predominance of a mixed population, in others people of Amerindian origin are a majority, some are dominated by inhabitants of European ancestry, while others are primarily of African descent. Most or all Latin American countries also have large Asian minorities. Europeans are the largest single group, and they and people of part-European ancestry combine to make up approximately 80% of the population of the subcontinent [61].

Latin America is one of the world's principal culture regions. It is distinguished from other world regions by a set of common cultural traits that include language, religion, social values, and civic institutions deriving principally from the Iberian Peninsula. Spanish and Portuguese are predominant languages. Catholicism is practiced by a vast majority of the region's inhabitants, and social customs and civic institutions bear many similarities to those in Spain. Nevertheless, the region is not culturally monolithic. Indigenous cultures and peoples have influenced national and subnational cultures within region, affecting language, religion, music, food habits, social customs, and civic institutions. The descendents of African slaves have also influenced the region's culture, although their effects have been most pronounced in Brazil, the Caribbean, and coastal areas of Central and northern South America. The cultural impact of other immigrants, including those from Italy, Asia, the Middle East, and even a few from North America has been minor[46].

Procedures

In order to examine the diversity of animals used in traditional medicine in Latin America, all available references or reports of folk remedies based on animal sources were examined [4, 7–11, 29–31, 36, 38, 40, 42, 62–193]. Information was gathered from published articles, books and book chapters, theses and dissertations, undergraduate theses, as well as from reports, and abstracts available at international online databases such as Web of Science, Scopus and Google Scholar and journals' web sites. The resulting database encompassed information on species, family names, and conditions to which remedies are prescribed. Only taxa that could be identified to species level were included in the database. Scientific names provided in publications were updated according to the ITIS Catalogue of Life: 2011 Annual Checklist [194].

Medicinal fauna of Latin America

The use of medicinal fauna in Latin America has been the focus of some ethnozoological research over the last two decades, mainly in countries such as Brazil, Mexico and Bolívia. These studies have demonstrated the importance of zootherapy to both urban and rural populations. This is not surprising, considering the rich biological resources and cultural of the region, that generated invaluable local knowledge systems that include extensive information on animal uses in general and medicinally useful species, in particular.

A review of the literature revealed that at least 584 animal species have been used in traditional medicine in Latin America (Table 1). The high number of animals used as medicine is not surprising given the important role played by wildlife as a source of medicines in different parts of the world. Nevertheless, the number is certainly underestimated since the amount of studies on the theme are very limited. It is self-evident that there is an urgent need for more studies into zootherapeutic practices in the region.

Table 1 Medicinal animals and its respective uses in popular medicine in Latin America
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The species catalogued comprised 13 taxonomic categories, belonging to 215 families. The groups with the largest numbers of medicinal species were: mammals (with 130 species), followed by birds (122), fishes (110), reptiles (95) and insects (54) (Figure 1). Most medicinal animals recorded are vertebrates. Species of this group are also used frequently at countries of Europe, Africa and Asia countries[16, 27, 33, 34, 37, 39, 195–197]. Examples of animals used as medicine in Latin America is shown in Figure 2.

Figure 1
figure 1

Number of animal species used as remedies per taxonomic category in Latin America.

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Figure 2
figure 2

Examples of animals used as medicine in Latin America. A: Chelonoidis carbonaria, B: Podocnemis expansa, C - Tupinambis merianae, D - Iguana iguana, E - Boa constrictor, F - Caudisona durissa, G - Cariama cristata, H - Cerdocyon thous.

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Most animals used as medicine were native to the Latin America, with the exception of Hippocampus spinosissimus, H. trimaculatus and Panthera leo and domestic exotic species (eg. Bos taurus, Capra hircus and Ovis aries). This finding demonstrates the importance of local biodiversity in furnishing folk medicines, in agreement with previous studies [7, 8, 42] which observed that faunal composition, accessibility, and availability directly influence the types of zootherapeutic items used in any given region. The use of the local fauna generally reduces the acquisition costs of commercial agents, and our results are in agreement with Apaza et al. [32], who noted a reduction in the cost of acquiring animal products in regions with abundant faunal resources. The medicinal use of wild exotic animals in Latin America indicates existence of international trade routes for medicinal species, a situation previously reported by Convention on International Trade in Endangered Species of Wild Fauna and Flora - CITES [198]. One excellent example are the seahorses. According to Baum and Vincent [79], the largest market for dried seahorses in Central America was for use as Traditional Chinese Medicine. These authors reported that three retailers in Panama City's Chinatown imported an estimated total of 18-27 kg dried seahorses annually from Hong Kong. These included H. spinosissimus and H. trimaculatus, which are found in the Red Sea and Indian Ocean, South-east Asia and Australia.

Some widespread species are used in different countries, such as Tupinambis spp. and Boa constrictor (in Argentina and Brazil), Tapirus terrestris (in Brazil and Bolivia) and Caudisona durissa in Mexico and Brazil [8, 32, 38, 189]. Despite the fact that technical studies recording the use of animals in traditional medicine are all relatively recent, an analysis of historical documents and archaeological research indicated that animals have been used in traditional medicines since ancient times in Latin America [36, 99, 152–154, 199]. In Brazil, for example, animal species have been used medicinally by indigenous societies for millennia. During his voyage through the interior of Brazil in the nineteenth century, Von Martius [200] recorded many natural medicines used by the Amerindian tribes he encountered, such as fresh caiman fat applied to alleviate rheumatism [115]. Even today, caiman fat (Cayman latirostris, Melanosuchus niger and Paleosuchus palpebrosus) is used in rural and urban communities to treat rheumatism [8]. Some examples of animals that have been used in Brazil since colonial times include: Iguana iguana (Iguanidae), Caiman latirostris, Crotalus durissus, and Micrurus ibiboboca. Similarly, a historical revision of the therapeutic uses of animals as described in Colonial chronicles from Mexico [99] revealed a total of 27 birds used as medicinal resource, showing their importance on this issue for the Ancient Mexican people.

Illnesses and remedies

Animal-derived remedies were used for treating various diseases (See Table 1). A single illness could be treated by various animal species (e.g., 215 animal species were used in the treatment of asthma and 95 in the treatment of rheumatism), and many species were prescribed for treating multiple illnesses, as in the case of the products obtained from the teju (Tupinambis teguixin) and the snake boa (Boa constrictor), which were indicated to treat 29 and 30 conditions, respectively. The reported multiple therapeutic actions and the use of various animals for the same condition presumes different properties either of parts used or of modes of preparation, corroborating the remark by Iwu [201] that different chemical constituents are enhanced by different factors, such as preparation, dosage, or part used. Additionally, the possibility of using various remedies for the same ailment is popular because it permits adapting to the availability of the animals [7]. The fact that some medicinal animals are being used for the same purpose suggest that different species can share similar medicinal properties and might indicate the pharmacological effectiveness of these zootherapeutic remedies.

Ingredients reportedly used in the preparation were fat, flesh, bone, bone marrow, cartilage, skin, tail, feather, liver, bile ("fel"), milk, rattle (from rattlesnakes), spine, shell, honey, wax, scale, rostral expansion, otolith, penis, carapace, blood, gizzard, beak, cocoon of insects, teeth, tongue, egg, egg shells, tibia, secretions, head, heart, urine, foot, legs, nest, guts, bezoar, ear, paw, spawn, nails, horn, sucking dish, eye, or more rarely, whole animals (Figures 3 and 4). Zootherapeutic products are consumed in several ways. Hard parts, such as teeth, nails, shells, rattles from snakes, fish scales, bone and cartilage generally are sun-dried, grated and crushed to powder, being then administered as tea or taken during meals, while fat, body secretion and oil are either ingested or used as an ointment. The influence of Westernization was also reflected in the presentation of some zootherapeutic products, which were either manufactured or pre-packaged. Examples are the fat extracted from the manatee (Trichecus sp.), sold as tablets, and the fat of Amazon River turtle (Podocnemis expansa (Schweiger, 1812)--Podocnemididae) sold as a manufactured soap in Brazil [42].

Figure 3
figure 3

Examples of animal products used as remedies in Latin America (Brazil). A - Tamanquaré (Uranoscodon superciliosus), B - Rattle of rattlesnake (Caudisona durissa), boas' head (Boa constrictor) and cayman's head (Cayman sp), C - Cayman's skin (Cayman sp.) and D - Shark jaws and teeth.

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Figure 4
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Medicinal animal products sold in Brazilian cities. A - Dried seahorses, B - Soap is produced from fat of turtle P. expansa and honey bee, C - Fat derived from sheep (Ovis aries) and Turtle (P. expansa), D - Anaconda fat (Eunectes murinus), E - Boa fats (Boa constrictor) and manatee (Trichecus sp.), F - Plastic bottles with raccoon fat (Procyon cancrivorus), rattlesnake (Caudisona durissa), caymans (Paleosuchus palpebrosus or Cayman crocodilus) and armadillo (Euphractus sexcintus), G - Head and fat of boa (B. constrictor) and rattle and fat of rattlesnake (C. durissa), and H: Oyster powder (Crassostrea rhizophorae), fats of different animals prompt to be commercialized right in big pots of plastic and in small flasks.

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In many cases, the therapeutic use of animal remedies appears to be based on morphological or behavioral peculiarities of the animal in question. In México, for example, a tea made from the toasted and ground penis of the coatimundi (Nasua narica or N. nasua) is considered the most potent remedy for male impotence [8, 40]. Descola [202] has recorded a similar remedy among the Achuar Jivaro of the Ecuadorian Amazon and provides an enlightening account of its probable origin: "The penis of the coati rejoices in a long fine bone that keeps it constantly rigid. This anatomical peculiarity has made a forceful impression upon the imagination of the Indians, and the men make the most of it, grating the bone into a decoction of green tobacco to make a love philtre. Quaffed at the right moment, it is reputed to prevent any flagging of the male member." In Brazil, reptiles that move slowly ("lerdos") are used to calm people ("lerdar"). For example, the products produced from U. superciliosus (dust and water) are used to "amansar" (to calm an aggressive person or ease the anger of someone betrayed by their wife or husband) [142]. There is an association between the biological characteristics of a lizard and the effects its use is expected to generate [134]. This observation is similar to that of Radbill [203] who pointed out that in homeopathic or imitative magic, it is assumed that certain qualities attributed to animals can be transferred to humans, and that this transfer can occur by inhalation, ingestion or application of the body parts of those animals.

It is worth mentioning that such "natural modeling" does not necessarily preclude empirical efficacy. In Oxchuc, México, the two most common medicines given to speed delivery in cases of protracted labor are made from the toasted tail and shell of the nine-banded armadillo (Dasypus novemcinctus) and the tail of the Virginia opossum (Didelphis virginiana) [40]. Both animals are characterized by odd reproductive habits: Nine-banded armadillos regularly give birth to litters of identical quadruplets, and the opossum produces 10 to 20 offspring per year (no doubt owing to its 13-day gestation period, one of the shortest in the animal kingdom [204]. While these reproductive anomalies undoubtedly influenced their therapeutic use, the tail of the Virginia opossum has demonstrated uterotonic action in recent laboratory and clinical trials. This action probably derives from the presence of prostaglandins, which are known to be oxytocic in very small doses [205].

Some diseases affect both animals and humans and can be treated with similar remedies. This way, some animals are used in ethnoveterinary medicine and are also used for the treatment of human diseases. Barboza et al. [193] and Souto et al. [62] recorded the utilization of animals (zootherapeutics) as sources of medicines in folk veterinary medicine in semiarid northeast Brazil and verified that 46 animal species (43 vertebrates and 3 invertebrates) are used in the prevention or treatment of veterinary diseases in that region. Souto et al. [62] pointed that parallels between zootherapeutic practices in human and animal ethnomedicine not only include the types of animals used and the prevalence of use of those wildlife resources, but also in the modes of administration of these remedies and the ethnomedical techniques employed. This view of ethnomedicinal symbioses was highlighted by McCorkle and Martin [206], who noted that nearly all the ways in which ethnopharmaceuticals are administered (both externally and internally) are shared in animal and human treatments. Souto et al [62] recorded that local residents in the semi-arid region of Brazil administer zootherapeutic medicines topically (powders, ointment of fats, and others), or orally to their livestock and pets in a manner very similar to human Complementary Alternative Medicine practices. The main techniques of preparing and administering animal-based remedies in local traditional medicine systems are commonly reported in Complementary and Alternative Medicinal practices in most parts of Brazil [7–9, 31, 132]. The close relationships between ethnoveterinary and human ethnomedicines can be easily explained from this perspective, as the main stock animals (e.g. cattle, sheep, goats, pigs, etc.) are mammals [132] that often have health problems very similar to humans and identical symptoms [62].

Cultural beliefs

Historically, traditional cultures recognized the importance of belief and expectancy within the healing encounter and created complex rituals and ceremonies designed to elicit or foster the expectancy and participation of healer and patient, as well as the community as a whole. Spiritual healing techniques have been a fundamental component of the healing rituals of virtually all societies since the advent of man [207, 208].

Folk-illnesses exist within the cultures that create them, "etiology, diagnosis, preventive measures and regimens of healing" [209] being provided by the culture. Cultural issues are recognized as important components of the provision of effective health care [210]. As noted by Straker [211], the supernatural world is as relevant in the diagnosis of illness as the natural world, with the main causes of illness being magical, mystical and animistic forces. Maher [212] showed that Aboriginal people have categorized illness as natural, environmental, direct supernatural, indirect supernatural and emergent or western causes. Pieroni and Quave [213] found, in a study carried at Ginestra/Zhure, Italy, that the aetiologies of various folk-illness are commonly linked to spiritual transmission, and that the treatments were often magical or psychotherapeutic in nature. Furthermore, for many illnesses deriving from relations with the supernatural, modern medicine is considered ineffective[214].

Besides their role in healing, natural products often have magical-religious significance, reflecting the different views of health and disease that exist within different cultures. In this context, animal parts are used to prepare clinical remedies as well as to make amulets or charms used in magical/religious diagnoses. Popular beliefs usually affect the way species are used in zootherapy [7, 8, 29, 134, 146]. One form of spiritual treatment involves the use of amulets containing reptile parts to protect the user from the "evil-eye" or from diseases. An example is caiman teeth (C. latirostris, M. niger, and P. palpebrosus) used as protection against snake bites [8].

The influence of magical beliefs integrated into traditional medicine is apparent [8]. In Brazil, for example, different animal species are used in magical-religious practices of Afro-Brazilian cults [29, 65, 142, 215, 216] in the context of rituals that emphasize the holistic nature of traditional medicine and that are designed to address spiritual, physical, and social-psychological problems [42]. Because medical systems are organized as cultural systems, the use of animal substances should be understood according to a cultural perspective [64].

Socio-economic aspects of zootherapy

In addition to the belief systems, socioeconomic aspects also influence zootherapeutic practices [8]. Latin America has one of the greatest disparities in income distribution in the world. Overall, the health profile of the Latin American population can be classified as undergoing a slow epidemiological transition. At one extreme of the spectrum there is a high incidence of (and mortality from) chronic noninfectious diseases such as cardiovascular problems and cancer, which predominate in large metropolitan areas. On the other hand, infectious diseases still impose a heavy burden on the poverty-stricken parts of the population. The reasons for this dichotomy are two-fold: uneven socioeconomic development within countries and the extreme diversity of regional environments [217].

Studies suggest that Indigenous peoples of Latin America still have inadequate access to mainstream health services, and health prevention and promotion programmes, and that services that do exist are often culturally inappropriate [218, 219]. The traditional medicine is widely available and affordable, yet in remote areas, and generally accessible to most people. In many developing countries, a large part of the population, especially in rural areas, depends mainly on traditional medicine for their primary health care, because it is cheaper and more accessible than orthodox medicine [8]. Traditional medicine is also more acceptable because it blends readily into the peoples' socio-cultural belief system [220–222]. Hence, resorting to the use of medicinal animals and plants, which were easily accessible and relatively cheap is an important component to healthcare in these gettings [8].

Health Concerns

Traditional drugs and traditional medicine in general represent a still poorly explored field of research in terms of therapeutic potential or clinical evaluation. There is a current preoccupation about this, since it is well-established that all sorts of vegetable, animal and mineral remedies used in a traditional setting are capable of producing serious adverse reactions. It is essential, however, that traditional drug therapies be submitted to an appropriate benefit/risk analysis. De Smet [223] draws attention to the fact that some side-effects of traditional medicines have proven to be more severe than the disease that they are treating. Such considerations must be taken into account, further highlighting the need for clinical studies of traditional remedies.

Numerous infectious diseases can be transmitted from animals to humans [224]. Zoonoses constitute other animal health problems that affect public health. These represent an important threat for the welfare of human populations. In the urban and rural areas of the countries under development, zoonoses continue to present high frequencies [225]. In this context, the possibility of transmitting infections or ailments from animal preparations to the patient should be seriously considered [224]. Several organs and tissues including bones and bile can be a source of Salmonella infection causing chronic diarrhoea and endotoxic shock. The possibility of transmission of other serious and widespread zoonoses such as tuberculosis or rabies should be considered whenever animal tissues from unknown sources are handled and used as remedies [226].

Several species of animals have become a favorite target of hunters because its bones, organs and tissues are used in traditional medicine [136, 143]. Indeed, numerous species of animals are hunted (poached) rather for their meat than for their supposed medical use [136, 140]. Nevertheless, there is often an overlap between the two purposes, and transmission of disease can occur in both instances. One excellent example of this regards the primates [140]. Several species of monkeys have been identified as harboring infectious diseases transmissible to man with potentially grave consequences [224, 227]. The related risks can be illustrated by a recent case from a Safari Park in Great Britain, where a colony of otherwise clinically healthy Macaque monkeys had to be humanely destroyed once it had been discovered that the monkeys harbored the simian herpes B virus [228]. While the agent is not harmful to monkeys, it causes mortality in 80% of affected humans. Certain researchers seriously consider the hypothesis that the worldwide epidemic of the HIV virus (causing the AIDS infection in humans) might have been initiated by transmission of a virus from monkeys several decades earlier [229].

The effectiveness of most of the medicines from wild animals/wild animal parts has not been scientifically studied and proven and their potency in many cases may be questionable. As pointed out by Pieroni et al. [230] the chemical constituents and pharmacological actions of some animal products are already known to some extent and ethnopharmacological studies focused on animal remedies could be very important in order to clarify the eventual therapeutic usefulness of this class of biological remedies. However, research with therapeutic purposes into the products of the animal kingdom has been neglected until recently [25, 231]. In comparison to research done on plant drugs, modern pharmacology has done far fewer studies on animal products and minerals [232].

Historically, traditional use of plants as medicines has been extensively recognized, studied, and reviewed. However, such attention has not been paid to the potential of animals as a source of medicinally relevant substances. A excellent example of this potential is provided by insects. Trowell [233] points out that there are at least 16 times as many insect species as there are plant species, yet plant chemistry has been studied 7000 times as much as insect chemistry when comparing the amount of research per species. Nonetheless, the vast biodiversity which exists in the arthropod world, compared to all other organisms on earth, certainly suggests that arthropods should be given a more serious look [234]. Nevertheless, in last years, there has been increasing attention paid to animals, both vertebrates and invertebrates, as sources for new medicines [235].

Environmental Approach

Various authors have discussed the conservation implications of the use of medicinal products derived from wild animal species [16, 33, 34, 143, 236]. In Latin America, as evidenced in the present review, the medicinal fauna is largely based on wild animals, including many endangered species.

The use of medicinal animals is common in both rural and urban areas. Biological remedies are openly commercialized in towns and cities, principally in public markets. It is common to find specific places in these markets where plants and animals are sold for medicinal purposes [31, 32, 38, 42, 66, 67, 131, 133, 135, 138, 144, 237]. The commercialization of animals for medicinal purposes is a widespread phenomenon, with significant implications for their conservation and sustainable use [1]. Previous authors [238–242] have suggested that market expansion induces people to make greater use of wild animals for traditional medicine and that the practice has spread in developed nations of Asia and the Pacific (e.g., Taiwan, Australia). But other research suggests that the increasing use of animals for traditional medicine can also take place without economic prosperity. For example, Kritsky [242] reported that the use of insects for traditional medicine in China increased during the Cultural Revolution. Based on an ethno-zoological survey of the use of medicinal birds, Joseph [243] concludes that the use of birds to treat human ailments increased in Madhya Pradesh, Central India, because people could not afford modern treatments.

The worldwide market for animal parts and their medicinal derivatives is contributing to the loss of some species. The increased use of medicinal animals has led to over-exploitation of species like rhinos, tigers, musk deer, bears, monkeys and pangolins. In spite of international regulations and several national laws against poaching and heavy penalties for culprits, the extremely high prices offered for the parts of some species serve as strong incentives for illegal trade in animal parts to flourish [1, 2].

It must be emphasized, however, that many factors affect animal populations in the world, and the use of these animals for medicinal purposes is only part of the problem. As such, the medicinal use of animals must be considered together with other anthropogenic pressures, such as habitat loss. The depletion of medicinal resources not only poses a challenge for conservation but represents a serious threat to the health of many human communities, and that efforts to stabilize the status of these species are important not only to conservationists but to millions of people whose health depends of the use of traditional remedies [136, 140, 224]. Moura and Marques [74] pointed that one characteristic in common among all zootherapeutic products, whether whole animals or their parts, is their lack of use for other purposes. In this sense, it is remarkable that in most cases, the medicinal products of animals are by-products from animals hunted for other purposes; thus, these multiple uses (including medicinal) of fauna and their impact on animal populations must be properly assessed and taken into consideration when implementing recovery plans for these species, especially those that are highly exploited [7–9, 31, 140]. Medicinal species whose conservation status is a cause of concern should receive urgent attention, and aspects such as habitat loss/alteration should be discussed in connection with present and future use of these species in folk medicine [8]

Zootherapy is intertwined with sociocultural and religious beliefs that must be understood by those engaged in modern conservation and protection of biodiversity. Celso [244] pointed out that natural medicine is one important use of biodiversity. Some traditional medicinal systems, like the Chinese Traditional Medicine, is recognized by the World Health Organization (WHO) and accepted by one-fourth of the world human population, and the reliance on traditional medicinal uses of animals by communities around the world should be addressed when designing strategies to conserve biodiversity. Conservation permits the continuing use of the resources in ways that are non-destructive and sustainable, while from the pharmaceutical point of view, it provides time to eventually demonstrate fully the potentially medicinal value of the resources [245].

Connections between traditional medicine, biodiversity and human health have recently been addressed by different authors [1, 22, 246–248]; have drawn attention to the fact that biodiversity loss can have indirect and direct effects on human well-being as well. The reliance on traditional uses of animals as food and as medicine by communities around the world highlights the need for further interdisciplinary research in ethnozoology which can be used in strategies to conserve biodiversity [53, 249]. Furthermore, loss of wildlife resources, aside from threatening people's health and well-being, affects their cultural integrity. In Latin America, despite the many individual efforts of the governments to preserve the biodiversity for future generations, traditional knowledge, especially that derived from indigenous knowledge (such as Traditional Medicine), is also disappearing [45]. In this sense, understanding the contexts of traditional therapeutic uses of animals, is central for elucidating their potential impact in public health and biodiversity conservation.

Conclusions

Latin America has a wealth of biological resources and is home to a large number of different ethnic and cultural groups, many of which have developed their own, distinct health care systems. As a result, the region is rich in traditional medicinal knowledge and zootherapy represents an alternative to official medicinal practices in rural areas and has also become part of urban popular medicine. Our results reveal that at least 584 animals are used for medicinal purposes in Latin America, underlining the importance of zootherapy as alternative therapeutic in region.

Animals provide the raw materials for remedies used to treat physical and/or spiritual diseases. Besides being influenced by cultural aspects, the relations between humans and biodiversity in the form of zootherapeutic practices are conditioned by the social and economic relations between humans themselves. In a region like Latin America, where the majority of the population has no access allopathic medicine, local medicinal animals and plant knowledge systems is of significance. The population uses traditional medicine due to the relatively low cost and difficult access to modern health facilities. Nevertheless, the interest in and intrinsic value of zootherapy not be only be attributed to the lack of access to modern medicinal services. Even in cities where modern health services are more accessible and specialized; many people continue to go to traditional healers showing the cultural acceptability of such practices.

Threatened species represented important medicinal resources in Latin America. This shows the need to integrate traditional knowledge into strategies to conserve and manage faunistic resources. Sustainability of harvesting of medicinal animals is challenged by many factors, from both social and ecological perspectives. It is important to respect differing views of the value of wildlife, while, at the same time, conserving biodiversity.

Using animal products as components of bioprospecting has implications for medicine, the environment, economy, public health and culture. Although widely diffused, zootherapeutic practices remain virtually unstudied, and so far there has been neither a demonstration of the clinical efficacy of the popularly used remedies nor an evaluation of the sanitary implications of the prescription of animal products for the treatment of diseases in the Latin America. New studies of medicinal fauna, which seek a better understanding of this form of therapy - including ecological, cultural and pharmacological aspects, are necessary.