China
Africa
Explore chapters and articles related to this topic
An Overview of Parasite Diversity
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2023
Eric S. Loker, Bruce V. Hofkin
Similar considerations apply to arthropod vectors that transmit disease, which often exist in cryptic species complexes, the species of which vary in their vectorial capacity. The Anopheles culicifacies complex involved in malaria transmission in India and the Simulium damnosum complex involved in the transmission of onchocerciasis in Africa are two prominent examples.
An Overview of Parasite Diversity
Published in Eric S. Loker, Bruce V. Hofkin, Parasitology, 2015
Eric S. Loker, Bruce V. Hofkin
Revealing such diversity is important because the individual species involved in cryptic species complexes may have very different modes of transmission or patterns of host use. For example, the different cryptic diplostomoid species inhabit different organs in their fish hosts and revealed patterns of host specificity not previously known. A full accounting of such diversity could give important clues for tracing the origins of outbreaks or explaining shifts to new host species. Some species of Trichinella are adapted to Arctic climates, whereas others thrive in the tropics, and the recognized species differ in host preference with some more likely to infect domestic swine, for example, than others. Similar considerations apply to the arthropod vectors that transmit disease. An example is the malaria-transmitting Anopheles mosquitoes, which often occur in complexes of cryptic species. Anopheles culicifacies, one of the major malaria vectors on the Indian subcontinent, is actually a complex of five cryptic species. The individual species differ in their geographic distribution, competence for hosting malaria, seasonal abundances, and response to insecticides, in addition to differences in the host species they prefer to bite. Our ability to fully understand malaria epidemiology is greatly enhanced if the cryptic species and their distinctive attributes are known.
Water-related insect vectors of disease *
Published in Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse, Routledge Handbook of Water and Health, 2015
Anomalously wet climatic conditions can lead to a dramatic increase in mosquito abundance, and epidemics can arise when regions of normally marginal transmission receive much rain (Kiszewski and Teklehaimanot, 2004). In much of the seasonal transmission zone of Africa, Anopheles gambiae sl mosquitoes develop in the shallow ephemeral pools that form as a result of monsoon rainfall (Figure 6.2). Because these pools must persist longer than the temperature-dependent development rate of the mosquito larvae in that pool, repeated rainfall or very heavy rainfall favor exponential growth of mosquito populations, and longer dry conditions kill the cohorts of developing larvae within the pools (Bomblies et al., 2008). However, it has been noted in African environments that very high intensity rainfall can wash larvae out of developmental habitat, diminishing the effect of rainfall-induced population amplification (Paaijmans et al., 2007). In addition, in wetter areas such as much of the equatorial rainforest of the world, mosquito abundance may not be limited by water availability. Instead, it may be limited by predators and parasites (Service, 1977), or potentially sunlight or nutrient availability. The connection of malaria dynamics to climate and hydrological factors does not fit one single mold. The local transmission of the disease depends greatly on the ecology of the primary vectors. For example, in contrast to the dominant environmental determinants of African mosquito populations, the Asian vector mosquito Anopheles culicifacies population has been responsible for a major epidemic during a dry period. An culicifacies develops along the banks of rivers, and tends to have low numbers during normal years (Carter, 1929; Rajendram et al., 1950; Wijesundera, 1988). However, during the period 1934–1935 two successive monsoons failed in Ceylon (now Sri Lanka), and there river flow slowed to a series of standing water pools, allowing a much greater surface area for mosquito development. Consequently, a devastating malaria epidemic struck Ceylon during a dry period (Reiter et al., 2004). Other malaria vectors throughout the world have their own specific behavioral ecology that can affect the population response to rainfall. Therefore, the relationship of mosquito abundance to water depends greatly on the local vector’s specific behavioral ecology.
Intensity of pyrethroid resistance in Anopheles culicifacies s.l. (Diptera: Culicidae) in Odisha State, India
Published in Pathogens and Global Health, 2020
Sudhansu Sekhar Sahu, Sonia Thankachy, Smrutidhara Dash, Gunasekaran Kasinathan, Ashwani Kumar
India is a highly malarious country contributing 10, 90,724 cases (89%) in Southeast Asia [1]. Among the six principal malaria vectors transmitting the disease in India, Anopheles culicifacies s.l. (Diptera: Culicidae) is the major widespread species contributing around 65% of malaria incidences in India [2]. Vector control program in the country mainly depends on indoor residual spraying (IRS) or long-lasting insecticidal nets (LLINs) [3,4]. Under the national anti-malaria program, dichlorodiphenyl-trichloroethane (DDT) was introduced in the early 1950s for vector control and later hexachlorocyclohexane (HCH) followed by malathion and recently synthetic pyrethroids (SPs) in 1990s were used to manage the insecticide resistance in An. culicifacies s.l [5]. Currently, LLIN is the prime tool for vector control in India [5]. The success of the intervention is based on the susceptibility of malaria vectors to pyrethroids. Currently, pyrethroids are the only class of insecticides used for LLINs production [6].
Utility of pf/pan RDT for diagnosis in the prevention of re-establishment of malaria in Sri Lanka
Published in Pathogens and Global Health, 2018
W.M.K.T. De A. W. Gunasekera, R.G. Premaratne, O.V.D.S.J. Weerasena, W.S. Premawansa, S.M. Handunnetti, S.D. Fernando
With the renewed global interest in malaria elimination in recent years, many malaria endemic countries are aiming to eliminate the disease. Since the year 2000, 18 countries and territories have been declared as no longer endemic or have reported zero indigenous malaria cases [1]. Sri Lanka, a tropical country, was certified as a malaria free country by World Health Organization (WHO) in 2016, but due to high receptivity and vulnerability, there is a risk of reintroduction of the disease [2]. Imported malaria cases continue to be reported in Sri Lanka with 57 cases reported in 2017. With Anopheles culicifacies being reported in most parts of the country, and the recent detection of Anopheles stephensi in the Northern region [3], early detection of imported malaria cases is essential to prevent the reintroduction of malaria to the country.
Impact assessment of Intensified Malaria Control Project in transitioning a high malaria-endemic district to a low-endemic district: an epidemiological aspect
Published in Pathogens and Global Health, 2023
Rahim Ali Ahmed, Avdhesh Kumar, Ananta Swargiary, Harpal Singh Suri, Hari Shankar, Syed Shah Areeb Hussain, Gaurav Kumar, Kuldeep Singh, Dipika Kalita, Afluza begum
In India, six species of Anopheles mosquitoes act as primary vectors for malaria transmission. These are Anopheles culicifacies, An. stephensi, An. minimus, An. dirus, An. fluviatilis and An. sundaicus. Additionally, the An. annularis, An. philippinensis, An. subpictus, An. nivipes, and An. varuna act as secondary vectors in limited geographical areas [5,6].