- Author: Kathy Keatley Garvey
His seminar begins at 4:10 p.m. and also will be on Zoom:
https://ucdavis.zoom.us/j/95882849672.
Host is UC Davis distinguished professor James R. Carey, UC Davis Department of Entomology and Nematology.
"African Trypanosomiasis, also known as 'sleeping sickness,' is caused by microscopic parasites of the species Trypanosoma brucei," according to the Centers for Disease Control and Prevention. "It is transmitted by the tsetse fly (Glossina species), which is found only in sub-Saharan Africa."
"Insect vectors attract small fractions of the funding spent on studying and controlling the diseases they transmit," Hargrove says in his abstract. "Emphasis on vector studies for tsetse (Glossina spp) have, however, resulted in several novel vector and disease control options. Experiments carried out over the past 60 years at Rekomitjie Research Station in the Zambezi Valley of Zimbabwe, together with daily meteorological readings, provide a platform for studying the effects of climate change on the population dynamics of tsetse species occurring around Rekomitjie. Rates of pupal production and development, of abortion rates and of mortality among immature and adult stages of the flies are all highly correlated with temperature. Methods used to estimate such relationships in the field will be discussed and the relationships are used in explaining the sudden collapse in tsetse populations during the past decade, consequent on significant increases in temperature, particularly in the hot dry season."
Hargrove served as the inaugural director of the South African Centre for Epidemiological Modelling and Analysis (SACEMA). The precursors for MMED and DAIDD were launched in 2006 at the beginning of his directorship; he has been involved continuously as an instructor in the program since, according to his biography on ICI3D. Over the past nearly 50 years, Hargrove has combined fieldwork and mathematical epidemiology to understand the population dynamics and control of tsetse flies, the vectors of human African Trypanosomiasis.
He focuses his current research on the modelling population dynamics, with a particular focus on how increasing temperatures in Africa will affect tsetse distribution. This work involves improving estimation of mortality in adult and immature stages of the fly. Since 1999, he has also focused on the analysis and modelling of data in the world of HIV. Current interest are in improving the use of biomarkers for the accurate estimation of HIV incidence.
He holds a bachelor's degree in zoology (1968) from the University of Oxford; a master's degree in biomathematics (1981) from UCLA, and a doctorate in insect physiology (1973) from the University of London.
Department seminar coordinator is urban landscape entomologist Emily Meineke, assistant professor. For technical issues regarding Zoom connections, she may be reached at ekmeineke@ucdavis.edu. (See complete list of spring seminars.)
Resource:
SERVIR--From Space to Tsetse Fly
World Health Organization: Trypanosomiasis (Human African Sleeping Sickness)
![John Hargrove in South Africa providing expertise on the tsetse fly. (Photo by Pietro Ceccato of the SERVIR Applied Sciences Team) John Hargrove in South Africa providing expertise on the tsetse fly. (Photo by Pietro Ceccato of the SERVIR Applied Sciences Team)](/blogs/blogcore/blogfiles/99078.jpg)
- Author: Kathy Keatley Garvey
He and other members of the research team are exploring the intact organs and tissues of tsetse flies using a powerful 3D X-ray imaging technique. The study, “Unraveling Intersexual Interactions in Tsetse”), is funded by the National Institute of Allergy and Infectious Diseases (NAIAD) of the National Institutes of Health.
“We started this project in 2019 and the work is ongoing,” said Attardo, an assistant professor in the UC Davis Department of Entomology and Nematology and chair of the Designated Emphasis in the Biology of Vector Borne Diseases. “We actually have scans of flies through the entire reproductive cycle, however, the segmentation is ongoing. We are working on developing ways to train artificial intelligence based software to assist us with the tissue segmentations.”
The tsetse fly transmits the parasite that causes the deadly human and animal trypanosomiasis, better known as African sleeping sickness, says Attardo, who is featured in a recently posted article, "A Detailed Look Inside Tsetse Flies," on the Berkeley Lab website. (See YouTube)
“The imaging technique provided new insights into how the flies' specialized biology governs mating and reproductive processes, including female flies' unique lactation and their delivery of a single fully developed larvae per birthing cycle – whereas most other insect species lay eggs,” according to the article. “The ALS (National Laboratory Advanced Light Source) produces X-rays and other forms of light for a broad range of simultaneous scientific experiments.”
Attardo, who specializes in medical entomology, reproductive physiology, molecular biology and genetics, says that tsetse flies resemble house flies, but are distinguished from other Diptera by their unique adaptations, including lactation and the birthing of live young. They carry only one offspring in their uterus at one time.
The parasite invades the central nervous system and disrupts the sleep cycle, says Attardo. “If not treated, the disease can result in progressive mental deterioration, coma, systemic organ failure and death.” An estimated 65 million people in 36 countries in sub-Saharan Africa are at risk for the deadly disease, according to the World Health Organization.
Attardo led a study, published in September 2020 in the journal Insects, detailing the ALS imaging work. The article, “Interpreting Morphological Adaptations Associated with Viviparity in the Tsetse Fly Glossina morsitans (Westwood) by Three-Dimensional Analysis,” received widespread attention. ALS experiments allow the researchers to create a detailed 3D visualizatiaon of the reproductive tissues without dissection and staining processes that introduce damage to the delicate samples.
“We want to understand what changes are happening during this process, how the process is being mediated, and if it can be manipulated to artificially repress females in the wild from mating,” Attardo told the Berkeley Lab News Center.
The Berkeley Lab is a multiprogram science lab in the national laboratory system supported by the U.S. Department of Energy through its Office of Science.
In his UC Davis lab, Attardo researches one of 35 tsetse fly species, Glossina morsitans morsitans, which prefers feeding on cattle to humans. Its strong mouthparts can easily puncture the tough cattle hide. In his lab, he feeds them warm cow blood.
Attardo holds a doctorate in genetics from Michigan State University, where he researched the molecular biology of mosquito reproduction in the lab of Alexander. Prior to joining the UC Davis faculty in 2017, Attardo worked for 13 years in the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health, first as a postdoctoral associate and then as a research scientist studying the reproductive biology of tsetse flies.
![UC Davis medical entomologist-geneticist Geoffrey Attardo is the principal investigator of a federal grant, UC Davis medical entomologist-geneticist Geoffrey Attardo is the principal investigator of a federal grant,](/blogs/blogcore/blogfiles/77886.jpg)
![A graphical abstract of the tsetse fly reproductive system. (Work of Geoffrey Attardo) A graphical abstract of the tsetse fly reproductive system. (Work of Geoffrey Attardo)](/blogs/blogcore/blogfiles/77887.jpg)
- Author: Kathy Keatley Garvey
The blood-sucking insect, which transmits the parasite that causes human and animal trypanosomiasis, has wreaked havoc in African countries.
It's distinguished from other Diptera by unique adaptations, "including lactation and the birthing of live young," says medical entomologist-geneticist Geoffrey Attardo, assistant professor, UC Davis Department of Entomology and Nematology.
Mark your calendar.
The UC Davis Department of Animal Science is hosting his seminar, “Tsetse Fly Reproduction: Exploration of the Unique Reproductive Adaptations of a Neglected Disease Vector” at 12:10 p.m., Monday, Oct. 7 in the Weir Room, 2154 Meyer Hall.
"Tsetse flies function as the sole vectors of human and animal Trypanosomiasis in sub-Saharan Africa," Attardo says in his abstract. "In addition to their role as disease vectors, tsetse flies distinguish themselves from other flies in terms of their amazing physiological adaptations. Of these adaptations, the reproductive biology/physiology of these flies stands out as one of the most dramatic."
"Female tsetse flies carry their young in an adapted uterus for the entirety of their immature development and provide their complete nutritional requirements via the synthesis and secretion of a milk like substance. Tsetse milk is derived of roughly 50 percent lipids and 50 percent proteins. Tsetse milk proteins are coded for by repurposed genes and by genes specific to tsetse flies. These genes are regulated in tight correlation with the female's pregnancy cycle. In addition, tsetse flies have established an obligate relationship with the bacterial symbiont Wigglesworthia glossinidius. This symbiont is required for lactation and larval development. Metabolic analysis of tsetse flies lacking this symbiont reveals a tightly integrated relationship between these organisms. This relationship is required for the metabolism of blood, production of essential micronutrients and synthesis/secretion of lipids essential for milk production.”
Attardo led landmark research published Sept. 2 in the journal Genome Biology that provides new insight into the genomics of the tsetse fly. The researchers compared and analyzed the genomes of six species of tsetse flies. Their research could lead to better insights into disease prevention and control.
“It was a behemoth project, spanning six to seven years,” said Attardo. “This project represents the combined efforts of a consortium of 56 researchers throughout the United States, Europe, Africa and China.” (See news story.)
In 1995, the World Health Organization (WHO) estimated that 60 million people were at risk of sleeping sickness, with an estimated 300,000 new cases per year in Africa, and fewer than 30,000 cases diagnosed and treated. Due to increased control, only 3796 cases were reported in 2014, with less than 15,000 estimated cases, according to WHO statistics.
WHO says that the parasitic disease “mostly affects poor populations living in remote rural areas of Africa. Untreated, it is usually fatal. Travelers also risk becoming infected if they venture through regions where the insect is common. Generally, the disease is not found in urban areas, although cases have been reported in suburban areas of big cities in some disease endemic countries.”
![Close-up of a gravid tsetse fly, Glossina morsitans morsitans. (Photo by Geoffrey Attardo) Close-up of a gravid tsetse fly, Glossina morsitans morsitans. (Photo by Geoffrey Attardo)](/blogs/blogcore/blogfiles/63453.jpg)
- Author: Kathy Keatley Garvey
But if you're UC Davis entomologist-geneticist Geoffrey Attardo, you do.
He led landmark research published Sept. 2 in the journal Genome Biology that provides new insight into the genomics of the tsetse fly, an insect that transmits the parasite that causes human and animal trypanosomiasis. In humans, it's commonly known as sleeping sickness, and if not treated, it's fatal.
Tsetse flies, Glossina sp., are of great medical and economic importance, wrote Attardo and co-authors Adly M. M. Abd-Alla of the Insect Pest Control Laboratory, Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria, and Serap Aksoy of the Yale School of Public Health, New Haven, Conn. They related that since the implementation of surveillance and record-keeping in the 20th century, “millions of people in sub-Saharan Africa” have died from sleeping sickness.
Their research compares and analyzes the genomes of six species of tsetse flies and could lead to better insights into disease prevention and control. “It was a behemoth project, spanning six to seven years,” said Attardo, an assistant professor in the Department of Entomology and Nematology. “This project represents the combined efforts of a consortium of 56 researchers throughout the United States, Europe, Africa and China.”
“The aim of these studies,” the authors wrote, “was to generate and mine the genomic sequences of six species of tsetse flies with different ecological niches, host preferences, and vectorial capacities. The goals of the analyses performed here are to identify the novel genetic features specific to tsetse flies and to characterize the differences between the Glossina species to correlate the genetic changes with phenotypic differences in these divergent species.”
“Expanded genomic discoveries reveal the genetics underlying Glossina biology and provide a rich body of knowledge for basic science and disease control,” the scientists concluded. “They also provide insight into the evolutionary biology underlying novel adaptations and are relevant to applied aspects of vector control such as trap design and discovery of novel pest and disease control strategies.”
Attardo, who joined the UC Davis faculty in 2017 after serving 13 years with the Yale School of Public Health, said the massive research project involved “the complete sequencing and assembly of six Glossina species, including the two primary vectors of human African tryapnosomiasis, three major vectors of animal trypanosomiasis and one ancestral tsetse species which demonstrates some resistance to the species of trypanosomes responsible for human and some animal forms of the disease.”
- A clearer definition of the Glossina phylogenetic tree and placement of a controversial species.
- Identification of rapidly evolving regions of the tsetse genome relative to Drosophila.
- Identification of Glossina specific genes and their functions as well as expansions and contractions of gene families in tsetse relative to other flies.
“We discuss the functional implications of these changes and how they relate to tsetses' physiological adaptations and evolutionary history,” Attardo noted.
“We discovered that the rhodopsin gene family which is associated with vision/color detection shows conservation in motion detection and tracking associated genes.” Attardo said. “However, the gene coding for the protein that detects blue wavelengths is divergent relative to houseflies and shows the highest variance between Glossina species of all the rhodopsin genes. This is significant as the color blue is used as an attractant to bring tsetse into the traps used for control. It suggests that different species may be tuned/attracted to different wavelengths of blue.”
They also analyzed the genes associated with tsetse immunity and the relative differences in comparison with houseflies and fruit flies. “We see many immune genes missing in Glossina and increased copy numbers of genes associated with negative regulation of immune function. We think this may be associated with the evolution of obligate symbiosis as a way to protect their symbionts.”
“We also found extreme conservation of milk proteins between all sequenced species,” the UC Davis medical entomologist said. “On the flip side, male reproductive proteins (seminal proteins) appear to be very rapidly evolving relative to the rest of the genome. The copy numbers of these genes also change significantly between species.”
The scientists also found an overall reduction of olfactory associated genes and protein modifications specific to salivary proteins in the two species that vector human trypanosomiasis.
In 1995, the World Health Organization (WHO) estimated that 60 million people were at risk of sleeping sickness, with an estimated 300,000 new cases per year in Africa, and fewer than 30,000 cases diagnosed and treated. Due to increased control, only 3796 cases were reported in 2014, with less than 15,000 estimated cases, according to WHO statistics.
The parasitic disease “mostly affects poor populations living in remote rural areas of Africa,” according to WHO. “Untreated, it is usually fatal. Travelers also risk becoming infected if they venture through regions where the insect is common. Generally, the disease is not found in urban areas, although cases have been reported in suburban areas of big cities in some disease endemic countries.”
Several National Institutes of Health (NIH) grants, awarded to Attardo and Aksoy, funded the research. They also drew funding from the McDonnell Genome Institute at Washington University School of Medicine; the National Research Foundation, the Swiss National Science Foundation, and the Slovak Research and Development Agency.
Related Links:
/span>![Eye-to-eye with a gravid (pregnant) tsetse fly, Glossina morsitans morsitans. (Photo by Kathy Keatley Garvey) Eye-to-eye with a gravid (pregnant) tsetse fly, Glossina morsitans morsitans. (Photo by Kathy Keatley Garvey)](/blogs/blogcore/blogfiles/63052.jpg)
- Author: Kathy Keatley Garvey
In humans, the disease is commonly known as sleeping sickness: the parasite invades the central nervous system and disrupts the sleep cycle. If not treated, the disease can result in progressive mental deterioration, coma, systemic organ failure and death.
The newly published research in the journal Genome Biology compares and analyzes the genomes of six species of tsetse flies and could lead to better insights into disease prevention and control. “It was a behemoth project, spanning six to seven years,” said Attardo, an assistant professor in the Department of Entomology and Nematology. “This project represents the combined efforts of a consortium of 56 researchers throughout the United States, Europe, Africa and China.”
Tsetse flies, Glossina sp., are of great medical and economic importance, wrote Attardo and co-authors Adly M. M. Abd-Alla of the Insect Pest Control Laboratory, Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria, and Serap Aksoy of the Yale School of Public Health, New Haven, Conn. They related that since the implementation of surveillance and record-keeping in the 20th century, “millions of people in sub-Saharan Africa” have died from sleeping sickness.
Tsetse flies, which resemble house flies, are distinguished from other Diptera by unique adaptations, including lactation and the birthing of live young, a vertebrate blood-specific diet by both sexes, and obligate bacterial symbiosis. The scientists targeted six Glossina genomes representing three sub-genera: Morsitans (G. morsitans morsitans, G. pallidipes, G. austeni), Palpalis (G. palpalis, G. fuscipes), and Fusca (G. brevipalpis) which represent different habitats, host preferences, and vectorial capacity.
“The aim of these studies,” the authors wrote, “was to generate and mine the genomic sequences of six species of tsetse flies with different ecological niches, host preferences, and vectorial capacities. The goals of the analyses performed here are to identify the novel genetic features specific to tsetse flies and to characterize the differences between the Glossina species to correlate the genetic changes with phenotypic differences in these divergent species.”
“Expanded genomic discoveries reveal the genetics underlying Glossina biology and provide a rich body of knowledge for basic science and disease control,” the scientists concluded. “They also provide insight into the evolutionary biology underlying novel adaptations and are relevant to applied aspects of vector control such as trap design and discovery of novel pest and disease control strategies.”
Attardo, who joined the UC Davis faculty in 2017 after serving 13 years with the Yale School of Public Health, said the massive research project involved “the complete sequencing and assembly of six Glossina species, including the two primary vectors of human African tryapnosomiasis, three major vectors of animal trypanosomiasis and one ancestral tsetse species which demonstrates some resistance to the species of trypanosomes responsible for human and some animal forms of the disease.”
The research, titled "Comparative Genomic Analysis of Six Glossina Genomes, Vectors of African Trypanosomes," offers:
- A clearer definition of the Glossina phylogenetic tree and placement of a controversial species.
- Identification of rapidly evolving regions of the tsetse genome relative to Drosophila.
- Identification of Glossina specific genes and their functions as well as expansions and contractions of gene families in tsetse relative to other flies.
“We discuss the functional implications of these changes and how they relate to tsetses' physiological adaptations and evolutionary history,” Attardo noted.
“We discovered that the rhodopsin gene family which is associated with vision/color detection shows conservation in motion detection and tracking associated genes.” Attardo said. “However, the gene coding for the protein that detects blue wavelengths is divergent relative to houseflies and shows the highest variance between Glossina species of all the rhodopsin genes. This is significant as the color blue is used as an attractant to bring tsetse into the traps used for control. It suggests that different species may be tuned/attracted to different wavelengths of blue.”
They also analyzed the genes associated with tsetse immunity and the relative differences in comparison with houseflies and fruit flies. “We see many immune genes missing in Glossina and increased copy numbers of genes associated with negative regulation of immune function. We think this may be associated with the evolution of obligate symbiosis as a way to protect their symbionts.”
“We also found extreme conservation of milk proteins between all sequenced species,” the UC Davis medical entomologist said. “On the flip side, male reproductive proteins (seminal proteins) appear to be very rapidly evolving relative to the rest of the genome. The copy numbers of these genes also change significantly between species.”
The scientists also found an overall reduction of olfactory associated genes and protein modifications specific to salivary proteins in the two species that vector human trypanosomiasis.
In 1995, the World Health Organization (WHO) estimated that 60 million people were at risk of sleeping sickness, with an estimated 300,000 new cases per year in Africa, and fewer than 30,000 cases diagnosed and treated. Due to increased control, only 3796 cases were reported in 2014, with less than 15,000 estimated cases, according to WHO statistics.
The parasitic disease “mostly affects poor populations living in remote rural areas of Africa,” according to WHO. “Untreated, it is usually fatal. Travelers also risk becoming infected if they venture through regions where the insect is common. Generally, the disease is not found in urban areas, although cases have been reported in suburban areas of big cities in some disease endemic countries.”
Several National Institutes of Health (NIH) grants, awarded to Attardo and Aksoy, funded the research. They also drew funding from the McDonnell Genome Institute at Washington University School of Medicine; the National Research Foundation, the Swiss National Science Foundation, and the Slovak Research and Development Agency.
Related Links:
![A gravid (pregnant) tsetse fly, Glossina morsitans morsitans. (Photo by Geoffrey Attardo) A gravid (pregnant) tsetse fly, Glossina morsitans morsitans. (Photo by Geoffrey Attardo)](/blogs/blogcore/blogfiles/63039.jpg)