Breaking News
January 22, 2019 - New machine learning algorithms identify early symptoms of urinary tract infections
January 22, 2019 - A global influenza pandemic high on the WHO’s agenda
January 22, 2019 - Amgen Makes All Repatha (evolocumab) Device Options Available In The US At A 60 Percent Reduced List Price
January 22, 2019 - Elastronics—hydrogel-based microelectronics for localized low-voltage neuromodulation
January 22, 2019 - Branched-chain amino acids in tumors can be targeted to prevent and treat cancer
January 22, 2019 - Fueling macrophages with energy to attack and eat cancer cells
January 22, 2019 - Amgen And UCB Receive Positive Vote From FDA Advisory Committee In Favor Of Approval For Evenity (romosozumab)
January 22, 2019 - Does being bilingual make children more focused? Study says no
January 22, 2019 - Study reveals new genes and biological pathways linked to osteoarthritis
January 22, 2019 - FSU study provides better understanding of spinal cord injuries
January 22, 2019 - Delaying bath for newborn babies increases breastfeeding rates, finds study
January 21, 2019 - WHO identifies non-communicable diseases as major threat to human health
January 21, 2019 - Many parents still try non-evidence-based cold prevention methods for children
January 21, 2019 - High Levels of Activity, Motor Ability Linked to Better Cognition
January 21, 2019 - Killer blows? Knockout study of pair of mouse MicroRNA provides cancer insight
January 21, 2019 - Buffalo researchers receive grant to quicken development of generic equivalents of contraceptives
January 21, 2019 - One-third of pregnant women do not believe cannabis is harmful to their fetus
January 21, 2019 - Fiderstat could be used as chemopreventative drug for intestinal cancers caused by APC gene mutations
January 21, 2019 - Modifying healthcare delivery practices may improve discussions between youth and healthcare providers
January 21, 2019 - UNIST researcher named as recipient of Merck’s 2018 Life Science Awards
January 21, 2019 - How Getting a Flu Shot Could Save Your Life
January 21, 2019 - Surgical adhesions can be treated, prevented in mice
January 21, 2019 - Increased physician-targeted marketing associated with higher opioid overdose deaths
January 21, 2019 - Researchers uncover specific microbial signatures of intestinal disease
January 21, 2019 - Researchers discover new blood vessel system in bones
January 21, 2019 - Simple blood test reliably detects signs of Alzheimer’s damage before symptoms
January 21, 2019 - Study to investigate new targeted oral treatments for severe asthma
January 21, 2019 - Plan Your Plate | NIH News in Health
January 21, 2019 - Fecal occult blood test may improve CRC outcomes in some
January 21, 2019 - Blood test detects Alzheimer’s disease years before symptoms develop
January 21, 2019 - Mount Sinai joins with Paradigm and ReqMed to repurpose drug for treatment of MPS
January 21, 2019 - FDA Advisory Committee Votes on Zynquista (sotagliflozin) as Treatment for Adults with Type 1 Diabetes
January 21, 2019 - The causes and complications of snoring
January 21, 2019 - Placenta adapts and compensates when pregnant mothers have poor diets or low oxygen
January 21, 2019 - New implant could restore the transmission of electrical signals in injured central nervous system
January 21, 2019 - Rapid-acting fentanyl test strips found to be effective at reducing overdose risk
January 21, 2019 - Coronary Artery Calcium May Help Predict CVD in South Asians
January 21, 2019 - The mystery of the super-ager
January 21, 2019 - Scientists develop smart microrobots that can change shape depending on their surroundings
January 21, 2019 - Keep Moving to Keep Brain Sharp in Old Age
January 21, 2019 - Despite progress, gay fathers and their children still structurally stigmatized
January 21, 2019 - New drug for treating liver parasites in vivax malaria
January 21, 2019 - Merck recognized with 2018 Life Science Industry Award for best use of social media
January 21, 2019 - Coeur Wallis equips the canton of Valais with 260 SCHILLER defibrillators
January 21, 2019 - Scientists propose quick and pain-free method for diagnosing kidney cancer
January 21, 2019 - Signs of memory loss could point to hearing issues
January 21, 2019 - HeartFlow Analysis shows highest diagnostic performance for detecting coronary artery disease
January 21, 2019 - How Much Caffeine is Too Much?
January 21, 2019 - Take a timeout before you force your child to apologize
January 21, 2019 - Scientists design two AI algorithms to improve early detection of cognitive impairment
January 21, 2019 - Novel therapy for children with chronic hormone deficiency provides lifeline for parents
January 21, 2019 - Bioethicists call for oversight of poorly regulated, consumer-grade neurotechnology products
January 21, 2019 - Study shows hereditary hemochromatosis behind many cancers and joint diseases
January 21, 2019 - Short bouts of stairclimbing throughout the day can improve cardiovascular health
January 20, 2019 - Liver Transplant Survival May Improve With Race Matching
January 20, 2019 - Study implicates hyperactive immune system in aging brain disorders
January 20, 2019 - Cancer Diagnosis May Quadruple Suicide Risk
January 20, 2019 - Parkinson’s disease experts devise a roadmap
January 20, 2019 - Research brings new hope to treating degenerative brain diseases
January 20, 2019 - Scientists pinpoint a set of molecules that wire the body weight center of the brain
January 20, 2019 - Researchers get close to developing elusive blood test for Alzheimer’s disease
January 20, 2019 - UCLA researchers demonstrate new technique to develop cancer-fighting T cells
January 20, 2019 - Researchers discover how cancer cells avoid genetic meltdown
January 20, 2019 - Exercise makes even the ‘still overweight’ healthier: study
January 20, 2019 - University of Utah to establish first-of-its-kind dark sky studies minor in the US
January 20, 2019 - School-based nutritional programs reduce student obesity
January 20, 2019 - Improved maternity care practices in the southern U.S. reduce racial inequities in breastfeeding
January 20, 2019 - New enzyme biomarker test indicates diseases and bacterial contamination
January 20, 2019 - Republican and Democratic governors have different visions to transform health care, say researchers
January 20, 2019 - Researchers discover that spin flips happen in only half a picosecond in the course of a chemical reaction
January 20, 2019 - Suicide Risk Up More Than Fourfold for Cancer Patients
January 20, 2019 - Doctors find 122 nails in Ethiopian’s stomach
January 20, 2019 - UV disinfection technology eliminates up to 97.7% of pathogens in operating rooms
January 20, 2019 - Researchers discover mechanism which drives leukemia cell growth
January 20, 2019 - AHA: Infection as a Baby Led to Heart Valve Surgery for Teen
January 20, 2019 - Injection improves vision in a form of childhood blindness
January 20, 2019 - Multiple sclerosis therapies delay progression of disability
January 20, 2019 - New study finds infrequent helmet use among bike share riders
January 20, 2019 - Clearing up information about corneal dystrophies
January 20, 2019 - Researchers describe new behavior in energy metabolism that refutes existing evidence
Temperature increases in Zambezi Valley may cause major declines in tsetse populations

Temperature increases in Zambezi Valley may cause major declines in tsetse populations

image_pdfDownload PDFimage_print

A new study, based on 27 years of data from Mana Pools National Park in Zimbabwe, suggests that temperature increases over the last three decades have already caused major declines in local populations of tsetse flies.

This analysis, published in the journal PLOS Medicine this week, provides a first step in linking temperature to the risk of sleeping sickness in Africa.

Tsetse are blood-feeding insects that transmit trypanosome pathogens which cause sleeping sickness in humans across sub-Saharan Africa. Without treatment, the disease is fatal. Parasites of this genus also cause nagana, animal African trypanosomiasis (AAT), in livestock. The most recent global estimates indicate that AAT kills approximately one million cattle per year.

The study is based on prolonged laboratory and field measures of fly densities from the 1990s, and nearly continuous records of climatic data since 1975, recorded by researchers based at the Rekomitjie Research Station in the park. Since the 1990s, catches of tsetse flies from cattle in the park declined from more than 50 flies per animal per catching session in 1990, to less than 1 fly per 10 catching sessions in 2017. Since 1975, mean daily temperatures have risen by nearly 1° C and by around 2° C in the hottest month of November.

Researchers from the Liverpool School of Tropical Medicine (LSTM), the South African Centre of Excellence for Epidemiological Modelling and Analysis (SACEMA) at Stellenbosch University, and the Natural Resources Institute at the University of Greenwich, developed a mathematical model, which showed that recent increases in temperature could account for the simultaneous decline of tsetse. The results provided evidence that locations such as the Zambezi Valley in Zimbabwe may soon be too hot to support tsetse populations.

“If the effect at Mana Pools extends across the whole of the Zambezi Valley, then transmission of trypanosomes is likely to have been greatly reduced in this warm low-lying region”, says Dr Jennifer Lord, lead author and postdoctoral fellow at LSTM.

While this would be good news for the disease situation in Zambezi Valley, rising temperatures may have made some higher, cooler parts of Zimbabwe, more suitable for the flies.

Professor John Hargrove, Senior Research Fellow at SACEMA, says the effect of recent and future climate change on the distribution of tsetse flies and other vectors, particularly mosquitoes, is poorly understood: “We don’t know, for example, whether the resurgence of malaria in the East African highlands in the 1990s was caused by rising temperatures or by increasing levels of drug resistance and decreasing control efforts.

“In general, the ways in which climate change will affect the spread of infectious diseases in sub-Saharan Africa is poorly understood because of sparse empirical evidence,” he adds.

However, work on tsetse and trypanosomiasis carried out at Rekomitjie over the past 59 years has produced long-term datasets for both vector abundance and climate change. The research station is located inside a protected area and has been free of agricultural activities since 1958. In 1984, the area was designated a UNESCO World Heritage Site. As not much has changed other than climate, the data from the site provided the ideal opportunity to develop a temperature-driven model for tsetse population dynamics.

Unlike mammals and birds, insects such as tsetse flies cannot regulate their own body temperatures, and their development and mortality rates are therefore strongly influenced by environmental temperatures. Pupae cannot survive at sustained temperatures below 16 or above 32° C. In addition, tsetse populations can become established in an area only if there are sufficient numbers of host animals and suitable vegetation to support tsetse, Prof. Hargrove explains.

He warns, however, that the Hwange National Park in Zimbabwe and Kruger National Park in South Africa are examples of areas where suitable hosts and habitat for tsetse are abundant. “Tsetse flies did occur in these areas in the 19th century, but they were always marginal because the winters there were rather too cold. With the massive rinderpest outbreak of the middle 1890s, when the vast majority of ungulates died, tsetse disappeared from these areas and have never established themselves again. But if temperatures continue to increase there is a danger that they may re-emerge.”

While tsetse-borne disease holds no danger for wildlife, as they have adapted to each other over millennia, control measures might have to be adopted in case tsetse re-occupy these parks and threaten cattle and humans nearby. According to Prof. Hargrove prophylactic drugs can protect livestock from the tsetse, but no such drugs are available for humans. The only sure way of protecting both livestock and humans is to attack the fly.

Source:

https://www.sun.ac.za/english/Lists/news/DispForm.aspx?ID=6035

Tagged with:

About author

Related Articles