Research

Our primary research interests are in the areas of environmental justice, climate change, applied and environmental health microbiology, food safety, water treatment, water quality, sanitation and hygiene. Our laboratory is focused on understanding the sources, transport and ecology of waterborne/based pathogens. We also have interest in developing advanced detection methods for emerging contaminants of concern and pathogens including enteric viruses and protozoan parasites.

Current projects:

Prevalence of Naegleria fowleri in Louisiana's private wells

Significance: Naegleria fowleri, also known as “the brain-eating amoeba”, is a free living amoebae found naturally in hot springs and warm surface waters. N. fowleri can cause primary meningoencephalitis (PAM), most often leading to death within 4 to 6 days if inhaled or forced into the nasal passages when swimming or diving. It is naturally found in soil and warm water and has a three stage life cycle. N. fowleri exists in soil in a cystic form and excysts to a flagellate stage when in contact with warm water and a source of food (bacteria). The flagellate stage feeds on bacteria at the air- water interface in hot springs, surface water, and other water systems that may remain still for prolonged periods.

In 2011, two people died of PAM caused by N. fowleri in DeSoto Parish and St. Bernard Parish, Louisiana. Both cases involved the use of a neti-pot. In 2013, there was second death in St. Bernard Parish (4-year old boy) caused by PAM and confirmed to be N. fowleri infection. Testing conducted in 2013 by Louisiana Department of Health and Hospitals (DHH)/CDC in both St. Bernard and DeSoto found this amoeba in the treated distribution system water supply. To date, a total of 7 Louisiana’s public water systems have tested positive for N. fowleri (Louisiana DHH). The purpose of this study is to determine the occurrence and quantity of the protozoan pathogen, N. fowleri, in groundwater sources in Louisiana.

Microbial Source Tracking and metagenomics studies in collaboration with the Lake Pontchartrain Basin Foundation

Significance:

Fecal contamination of surface water is one of the important issues in water resource management. Water contaminated with feces impacts public health by introducing enteric pathogenic organisms. Recreational waters, shellfish farms, beaches, and drinking waters may be compromised by faulty sewage systems, dysfunctional septic tanks, agricultural runoff, and wildlife. Additionally, fecal pollution adversely affects aquatic ecosystems. The detection of fecal pollution and identification of its source is imperative in assessing the health risk and eliminating its source. However, we still use fecal indicator bacteria (FIB) such as E. coli to identify the point source of fecal pollution. This source identification based solely on FIB has limitations in identifying the point source. The goal of our study is to use advanced molecular methods including qPCR, ddPCR and metagenomics to identify the source of fecal contamination. We will also implement a quantitative microbial risk assessment (QMRA) approach for prevention of waterborne disease outbreaks.

Citizen Science Project/Environmental Justice

This project uses a team approach to monitor water quality in New Orleans, concentrating its efforts in impaired water bodies of the Vietnamese Community in New Orleans East. The team is made up of staff from the EPA’s Gulf of Mexico (GMP) Program, Lake Pontchartain Basin Foundation, New Orleans Sewerage and Water Board and Tulane University. Some aims include:

• Disseminate water quality information to, local civic groups, LPBF and LA DEQ and the scientific/environmental community to aid in characterization and research studies

• Analyze data to assess trends in the waterbodies. Sites showing poor water quality will be further investigated and BMPs implemented.

• Improving WQ by working with a local champion to implement BMPs.

• Meet GMP performance measures - WQ and Education

• Work with inner city schools- EJ component

• Help students with community hours (WQ monitoring and developing/implementing BMPs)

We just signed a Memorandum of Understanding with the EPA GMP on Oct 11, 2016. The purpose of this MOU is to explore possible collaborations and ways to increase cooperation between TU and GMP in areas of mutual interest, including but not limited to the GMP. The implementation of program activities in this MOU is intended to promote equal opportunity in higher education, contribute to the capacity of the GMP to provide high-quality education, encourage participation of TU students and faculty in the GMP’s activities.

CAMP (CAnal Microbiome Project)

This project will investigate bacterial microbiome in different canal waters in New Orleans, LA.

Virus and protozoan reduction in advanced wastewater reclamation facilities

The US faces immediate challenges regarding the sustainability of freshwater supplies for urban and agricultural needs. In some locations, treated wastewater is the only remaining water resource that has not be completely utilized. Potable use of freshwater supplies that are influenced by municipal wastewater effluent is actually commonplace. Waterstressed areas must augment their drinking water source with alternative waters to satisfy projected demands. While most systems depend on indirect potable reuse with an environmental buffer to blend high purity reuse water with native waters, at least three US communities (Cloudcroft, NM, Big Springs TX, and Wichita Falls, TX) are developing direct potable reuse without a natural buffer. In addition, it is paramount to investigate the feasibility of developing criteria for direct potable reuse to mitigate severe drought. Although potable water reuse systems provide a sustainable water supply, the primary obstacle to implementation has been public and scientific concerns regarding unregulated or unknown chemical and biological contaminants. The goal of our study is to investigate the removal of selected enteric viruses and antibiotic resistance genes during wastewater treatment.

Coastal water quality/seafood safety focused on Vibrio spp.

Vibrio vulnificus is a gram-negative bacterium and an opportunistic human pathogen that occurs naturally in estuarine and brackish waters worldwide. It can cause severe wound infections often resulting in necrotizing fasciitis or “flesh eating bacteria”. It is responsible for 95% of seafood related deaths in US mostly associated with the consumption of raw oysters and shellfish. V. vulnificus levels have been reported to be highest during summer months (May to October) and when salinity is between 5-25 %.Our objectives include studying the occurrence of Vibrio vulnificus and fecal contamination in coastal waters of Louisiana, conduct a baseline study collecting water samples from various sites around the lake and attempt to identify abiotic and biotic factors related to their survival.

WaSH projects in Nepal post-2015 earthquake/ Irrigation water quality

The major earthquake (magnitude 7.8) occurred on April 25, 2015 in Nepal. An estimated 8670 fatalities and 2.8 million people were in immediate need of humanitarian assistance according to the government of Nepal. There were several aftershocks throughout the end of April followed by a major earthquake of 6.8 magnitude on May 12, 2015. Due to inadequate, interrupted, or intermittent treatment, public health authorities in Nepal have repeatedly associated waterborne disease outbreaks with unsafe drinking water. Nepal is also one of the poorest countries in the world and people can't afford water purification technologies such as the point-of-use (POU) filters which are effective on removing microbial pathogens. It is paramount that the earthquake victims have access to clean water and proper sanitation to prevent a major waterborne disease outbreak. At present, their major drinking water source is tanker water, which source is unknown and might be contaminated. During this catastrophic event, we conducted a preliminary qualitative study of drinking water quality and analyze free residual chlorine (FRC), Ammonia and coliform bacteria. However, we need to conduct a comprehensive and quantitative study of the problem of enteric pathogens in drinking water in various quake hit regions of Nepal.

The purpose of this study is to assess the impact of earthquake in drinking water quality and household sanitation in rural Nepal. The project will provide information to local regulatory agencies that can be used to develop guidance for protection of drinking water supplies post-quake in Nepal.

KAMP (KAthmandu Microbiome Project)

This project will investigate seasonal variation of opportunistic pathogens/overall bacterial microbiome in different sources of water in the Kathmandu Valley, Nepal.

Occurrence of opportunistic premise plumbing pathogens (OPPPs) in St. Joseph water distribution systems

The drinking water crisis in Flint, Michigan has raised public health concerns about lead exposure, the U.S. water supply infrastructure and the authority to enforce safe and sanitary conditions. At the same time, according to CDC, “incidence of Legionnaires’ disease has increased nearly 270% in the past 10 years”. In the town of St. Joseph, residents have suffered through years due to poor drinking water. St. Joseph is a small town in northeast Louisiana with a population of 1,176. It comprises 77.7% African-American and per capita income is $9,049. 37.8% are below poverty line in this town. Governor John Bel Edwards issued a Public Health Emergency Proclamation for the town on December 16, 2016. He signed the declaration, which stated: “The Town of St. Joseph has experienced water problems for years due to the poorly maintained and deteriorating water distribution system. Frequent breaks in the water distribution system provide a potential health risk because of the drop-in water pressure. Out of an abundance of caution, the Louisiana Department of Health recommends that residents use an alternative source of water for personal consumption, including making ice, brushing teeth or using it for food preparation and rinsing of foods.” The Public Health Emergency was based on lead levels detected in drinking water above the Primary Drinking Water Standard Action Level of 15 parts per billion. The Louisiana Department of Health tested for lead levels in tap water from homes and businesses from Dec 20, 2016 through January 20, 2017. They found that 98 samples had contained lead at or above the 15 ppb Primary Drinking Water Standard Action level. We quantified the concentration of OPPPs in drinking water and developed a citizen science program to implement best risk management practices by working with a local community-based non-profit organization- Ava J Shaw Foundation.