University of Costa Rica

About: University of Costa Rica is a education organization based out in San José, Costa Rica. It is known for research contribution in the topics: Population & Venom. The organization has 9817 authors who have published 16781 publications receiving 238208 citations. The organization is also known as: UCR & Universidad de Costa Rica.

Effects of aqueous extract of Casearia sylvestris (Flacourtiaceae) on actions of snake and bee venoms and on activity of phospholipases A2.

Abstract: The crude aqueous extract from the leaves of Casearia sylvestris, a plant found in Brazilian open pastures, was assayed for its ability to inhibit phospholipase A2 (PLA2) activity and some biological activities of bee and several snake venoms, and of a number of isolated PLA2s. The extract induced partial inhibition of the PLA2 activity of venoms containing class I, II and III PLA2s. When tested against the purified toxins, it showed the highest efficacy against class II PLA2s from viperid venoms, being relatively ineffective against the class I PLA2 pseudexin. In addition, C. sylvestris extract significantly inhibited the myotoxic activity of four Bothrops crude venoms and nine purified myotoxic PLA2s, including Lys-49 and Asp-49 variants. The extract was able to inhibit the anticoagulant activity of several isolated PLA2s, with the exception of pseudexin. Moreover, it partially reduced the edema-inducing activity of B. moojeni and B. jararacussu venoms, as well as of myotoxins MjTX-II and BthTX-I. The extract also prolonged the survival time of mice injected with lethal doses of several snake venoms and neutralized the lethal effect induced by several purified PLA2 myotoxins. It is concluded that C. sylvestris constitutes a rich source of PLA2 inhibitors.

The need for full integration of snakebite envenoming within a global strategy to combat the neglected tropical diseases: the way forward.

Abstract: Snakebite envenoming constitutes a serious medical condition that primarily affects residents of rural communities in Africa, Asia, Latin America, and New Guinea [1], [2]. It is an occupational, environmental, and domestic health hazard that exacerbates the already impoverished state of these communities [3]. Conservative estimates indicate that, worldwide, more than 5 million people suffer snakebite every year, leading to 25,000–125,000 deaths, while an estimated 400,000 people are left with permanent disabilities [4]–[7]. Eight thousand amputations are thought to be performed annually in Africa alone [8]. However, community-based surveys illustrate that the actual burden of human suffering is likely to be even greater [9], [10]. Despite this global impact, snakebite has received little attention from the global health community, the pharmaceutical industry, governments, and public health advocacy groups, and has a disappointingly low priority in the global health research agenda. As a consequence, the paucity of health programs addressing snakebite at national, regional, and global levels allows deaths or maimings of snakebite victims to continue. This burden of suffering could be significantly reduced because effective preventive and therapeutic resources are available, but, because of systemic neglect, they are not delivered in many regions. There has been progress in highlighting the neglect of snakebite. Thus, the inclusion of snakebite in the WHO list of Neglected Tropical Diseases (NTDs), and the development of initiatives by the WHO and its regional offices [1], [11] as well as by the Global Snakebite Initiative (GSI) [6] and other efforts at national and regional levels, have improved the global awareness of this disease. However, the impact of these projects has been rather limited, particularly in light of the progress made in control of the helminthic NTDs. Global efforts launched in the last decade to confront NTDs have recruited the important support of the World Health Organization (WHO), governments, diverse funding agencies, and other advocacy groups/foundations [12], [13]. As a result, there is a growing awareness of the sociomedical importance of this group of ancient human scourges. Several strategies are being implemented to reduce the burden of these diseases [13] within the framework of the Millennium Development Goals (MDGs). A significant achievement has been the conceptualization of NTDs as a group of health problems that share many common demographic, sociological, epidemiological, and clinical features. Implementing integrated initiatives conducted by advocates, involving research and development, control, treatment, and attention to the needs of affected populations, is now a primary strategy to reduce disease burden. Regrettably, snakebite, despite being included in the 2009 WHO list of NTDs, has not been incorporated into these globally coordinated efforts to reduce the impact of the NTDs. The reasons for this omission are diverse and are probably based upon the perception that, because snakebite is not an infectious disease, the strategies for its alleviation do not fit within the strategies used to combat the “typical” NTDs. This perception is misleading, since snakebite epitomizes the main features that characterize NTDs [13]: Snakebite causes significant rates of mortality, morbidity, disfigurement [6], and chronic psychological sequelae [14], and incurs a heavy loss of productivity due to physical disability. Since impoverished rural farmers are the group at highest risk [3], snakebite exerts a direct economic and social impact on families and communities and thereby significantly contributes to the prevailing vicious cycle of poverty and inequity. Since snakebite mainly afflicts low-profile, rural populations that lack a political voice, victims cannot influence regional and national administrative and political policy makers, and their needs remain largely unheard and politically neglected. Snakebite does not represent a health risk to high-income peoples and countries. This contributes to the negligible interest shown by governments to combat this problem with the financial and political resources appropriate to that task. Snakebite causes stigma and discrimination, especially in people suffering from venom-induced permanent physical deformity and disability, as well as from amputations and other surgical procedures employed in the management of these complications [8]. This affects working performance and greatly limits the chances of victims' finding jobs and leading productive and fulfilling lives. In addition, since a high proportion of cases occur in children, snakebite may have profound implications for their development, education, and future opportunities, blighting their entire lives. The true rates of snakebite-induced morbidity and mortality are still largely unknown in many regions of the world because estimates are based mostly on extrapolations of hospital statistics. Recent national community-based surveys have highlighted the fact that the actual magnitude of this disease is much greater than was previously thought because many snakebite victims never manage to reach hospitals and therefore remain unrecorded and invisible to the health system [9], [10]. The current estimate of 20,000 to 94,000 deaths caused by snakebite annually [5] is therefore bound to be an underestimate, making the burden of mortality from snakebite much higher than for other NTDs [6]. Snakebite has been largely omitted from research agendas and does not feature as a listed research priority for any health funding agency. Despite significant advances in the biochemical and toxicological understanding of snake venoms, including the realization of their potential as pharmacological agents, there are serious deficiencies in our knowledge of the epidemiological and clinical features of snakebite envenomings in many countries. There has also been negligible funding for research to improve the technologies for antivenom manufacture—the only validated therapy for snakebite envenoming. Likewise, topics related to economic impacts, public health policies, and cultural perceptions of snakebite have failed to attract the attention of research groups and their funders. The tragedy of snakebite is that effective solutions already exist but are not being delivered in many countries. Timely administration by a trained practitioner of effective and appropriate antivenoms can be expected to prevent most deaths and sequelae resulting from these envenomings. Although approved methods for antivenom production are readily available in the public domain, antivenoms are neither available nor accessible in many regions of the world [15]. Some distinctions between snakebite and the other NTDs pose significant challenges to establishing effective snakebite control programs. Thus, because it is not an infectious disease, there is no potential for elimination or eradication of snakebites, unlike the expectation for most other NTDs. Highly effective and logistically efficient mass vaccination or administration of antihelminthics, antibiotics, and other interventions, such as vector control, and provision of safe food, water, and sanitation [13], are not applicable to snakebite envenoming. Furthermore, unlike the near global effectiveness of most antihelminthics and antibiotics, snakebite envenoming therapy is regionally specific and this limits the implementation of “economics of scale” to antivenom production. Nevertheless, the fact that snakebite envenoming coexists with bacterial, viral, and parasitic NTDs in many rural settings suggests patterns of comorbidity that are amenable to integrated intervention. There are several features of snakebite control that are similar to the principal aspects used to combat the infectious NTDs, indicating that incorporation of snakebite prevention, treatment, and rehabilitation resources into the strategies to fight NTDs would offer a great health benefit to vulnerable communities. For example, encouraging the wearing of appropriate shoes, the use of a torch after dark, sleeping under an insecticide-impregnated bed net, and speeding patient transport to medical care in remote areas using trained volunteer motorcyclists (S.K. Sharma, personal communication, 2011) are all effective in reducing the incidence of snakebite [16]. These approaches would also reduce the burden of soil-transmitted helminthic infections, tropical and Buruli ulcer, podoconiosis, malaria, and kala-azar and other vector-borne infections. Most of the key elements of the WHO Global Plan to Combat Neglected Tropical Diseases 2008–2015 [13] also apply to reduce the burden of snakebite envenoming.

Reef coral reproduction in the eastern Pacific: Costa Rica, Panamá, and Galápagos Islands (Ecuador). II. Poritidae

Abstract: A comparative study of the reproductive ecology of the zooxanthellate, scleractinian corals Porites lobata Dana and P. panamensis Verrill was conducted from 1985 to 1991 in eastern Pacific reef environments that were severly impacted by the 1982–1983 El Nino warming events. P. lobata, a presumed broadcast spawner of large colony size, is widely distributed in the equatorial eastern Pacific, whereas P. panamensis, a brooder of small colony size, is abundant only on some reefs in Panama. Both species were gonochoric with nearly 1:1 sex ratios in large study populations except for P. lobata at Cano Island that had 14% hermaphroditic colonies. Mature, unfertilized oocytes contained numerous zooxanthellae in both Porites species, and all planula developmental stages contained zooxanthellae in P. panamensis. Year-round sampling revealed high proportions of colonies with gonads, ranging from 30 to 68% in P. lobata and from 60 to 68% in P. panamensis. No clear relationship between numbers of reproductive colonies and the thermal stability of the habitat was evident in P. lobata: percent colonies with gonads at non-upwelling sites was 48 to 68% at Cano Island (Costa Rica) and Uva Island (Panama), and at upwelling sites 30 to 50% at Saboga Island and Taboga Island (Panama), and the Galapagos Islands (Ecuador). Similarly, 90% of all P. panamensis colonies were reproductive at Uva Island (a non-upwelling site), and 86% were reproductive at Taboga Island (an upwelling site). Upwelling at Taboga Island is seasonal, nevertheless P. panamensis produced mature gonads or planulae over most of the year (11 mo), whereas P. lobata exhibited reproductive activity during only 2 mo (May and June). No clear lunar periodicity was observed in P. panamensis (Taboga Island), but a high proportion of P. lobata showed increased gonadal development around full and new moon, especially at Cano and Uva Islands. Estimated fecundities were relatively high for P. lobata at Cano (4000 eggs cm-2 yr-1) and Uva (5200 eggs cm-2 yr-1) Islands, and notably low (70 to 110 eggs cm-2 yr-1) in the Galapagos Islands. P. panamensis mean fecundity at Taboga Island was 720 planulae cm-2 yr-1 or 4.0 mm3 cm-2 yr-1, which was lower than the egg volume production of P. lobata at Cano and Uva Islands (7.0 to 10.0 mm3 cm-2 yr-1). The capacity of P. lobata and P. panamensis to reproduce sexually supports the notion that eastern Pacific coral reef recovery may not be dependent on long-distance dispersal from central Pacific areas. However, sexual recruits of P. lobata are absent or uncommon at all eastern Pacific study sites while recruits of P. panamensis were common to abundant only at the Uva Island study site. Asexual fragmentation in P. lobata augments recruitment locally, but plays no role in P. panamensis recruitment.