Tropical Health Matters

The United States has been assisting in the fight against malaria and tropical diseases throughout the tropics. The question now arises is it ready to tackle these diseases on the home front?

In recent months CBS News reported that “Malaria cases in Florida and Texas are first locally acquired infections in U.S. in 20 years,” according to CDC. Local transmission of these 8 cases is the key concern because there are always imported cases from travelers to malaria endemic areas throughout the year. This has led to better planning of mosquito control activities. All of the Florida cases were found in Sarasota County. Although Anopheles mosquitoes still existed in the environment, they had not been infected in recent years.

Likewise Pensacola News Journal noted that, “Rising evidence is pointing to the possibility that leprosy has become endemic in the southeastern U.S. with Florida being named among the top reported states.” The paper explains that these Leprosy cases in central Florida account for nearly 20% of the national total, and that the state is considering instituting contact tracing.

Chagas disease may affect up to 300,000 people from Florida across to California, but an Emerging Pathogens Institute report shared in the Apopka Voice, explained that most cases remain undetected. While Chagas primarily affects people who have immigrated from Latin America, researchers are discovering locally acquired cases because the vector, the kissing bug, has been found in 29 states, and thus local transmission now occurs.

An article in PLoS NTDs explains that Zika, Dengue, and Chikungunya viruses are spread in the southern and Gulf Coast states by members of the Aedes mosquito family, aided by changes in weather and climate patterns. Just as in other countries where NTDs are endemic, the US experience of these diseases also sees that, “poverty equates to substandard housing that exposes residents to insect vectors, a lack of access to sanitation and water, and degraded environments.”

Local, State and National health agencies in the US are starting to awaken to the fact that diseases which we thought were eliminated back in the mid-19^th-century are making a comeback. At a minimum, funding and training are needed to equip our Health Departments with environmentally appropriate vector control measures, appropriate treatment regimens, and disease surveillance tools to tackle the same problems that are threatening the lives of people throughout low- and middle-income countries throughout the world.

Various updates were found in newsletters and journal abstracts online today. These looked at mosquitoes – what attracts them to people, how ookinetes move in the midgut, and how perlite from volcanic rock may be a barrier repellent. Nigeria reports that there is no ACT resistance – so far.  And malaria partners join to coordinate actions in Uganda.  Click on links to read details.

Nigeria yet to detect resistance of malaria parasite to ACTs, says ministe

Contrary to reports that Africa has for the first time identified resistance strain of the malaria parasite to the drug of choice, Artemisinin Combination Therapy (ACT), the Minister of Health, Dr. Osagie Emmanuel Ehanire, on Monday said a study conducted in three states of the country showed there is no such phenomenon in Nigeria.  “However, we are still monitoring the situation. We insist that people should conduct a malaria test before using the drug of choice. This we hope will help prevent any kind of resistance of the malaria parasite to ACTs.”

Ministry of Health launches the Malaria Free Uganda Fund

Health Minister Dr Jane Ruth Aceng told journalists in Kampala today that the idea of having this new board was reached after realizing that different entities have been conducting the same malaria control related work. She said that the ministry resolved that mainstreaming responsibility will remove financial and operational bottlenecks that deter them from achieving set targets for elimination of the disease. The fund with a board of 11 members is chaired by Kenneth Wycliffe Mugisha of the Rotarian Malaria Partners-Uganda.

Volcanic Rock Yields a New Kind of Insecticide for Mosquitoes

Insecticide resistance to pesticides has become widespread in mosquito populations, making insecticides less effective over time. Therefore, there is an urgent need for insecticides with alternative modes of action. tested a material derived from volcanic rock, perlite, as a potential non-chemical insecticide against Anopheles gambiae, one of the primary mosquitoes that spreads malaria in Africa. In their new report published in August in the Journal of Medical Entomology, they show that perlite has encouraging potential as a mechanical insecticide. Perlite is believed to act by causing dehydration in the mosquitoes. read more…

Mosquitoes love pregnant, beer-drinking exercisers with Type O blood

Mosquitoes spread Zika, West Nile, Chikungunya, Dengue, and Malaria, resulting in 700 million illnesses a year and a million deaths. Even if you don’t get sick from a mosquito bite, the blood thinner they pump into your flesh before draining your blood causes swelling and itching. This article in Smithsonian Magazine lists the factors that make some people more tempting targets than others to mosquito bites. They include:

• Blood type: “One study found that in a controlled setting, mosquitoes landed on people with Type O blood nearly twice as often as those with Type A.”
• Carbon Dioxide: “people who simply exhale more of the gas over time—generally, larger people—have been shown to attract more mosquitoes than others.”
• Exercise: “mosquitoes find victims at closer range by smelling the lactic acid, uric acid, ammonia and other substances expelled via their sweat”
• Skin bacteria: “scientists found that having large amounts of a few types of bacteria made skin more appealing to mosquitoes”
• Beer: “Just a single 12-ounce bottle of beer can make you more attractive to the insects”
• Pregnancy: “pregnant people exhale about 21 percent more carbon dioxide and are on average about 1.26 degrees Fahrenheit warmer than others”
• Clothing color: “wearing colors that stand out (black, dark blue or red) may make you easier to find”
• Genetics: “underlying genetic factors are estimated to account for 85 percent of the variability between people in their attractiveness to mosquitoes”

Live In Vivo Imaging of Plasmodium Invasion of the Mosquito Midgut

Malaria is one of the most devastating parasitic diseases in humans and is transmitted by anopheline mosquitoes. The mosquito midgut is a critical barrier that Plasmodium parasites must overcome to complete their developmental cycle and be transmitted to a new host. Here, we developed a new strategy to visualize Plasmodium ookinetes as they traverse the mosquito midgut and to follow the response of damaged epithelial cells by imaging live mosquitoes. Understanding the spatial and temporal aspects of these interactions is critical when developing novel strategies to disrupt disease transmission.

March 3rd marks the annual World Health Day. The World Health Organization explains that the purpose of this day is to raise awareness on how to prevent deafness and hearing loss and promote ear and hearing care across the world. WHO notes that, “Unless action is taken, by 2030 there will be nearly 630 million people with disabling hearing loss.”

Factors associated with health loss and disability include ageing of the population, environmental noise exposure, certain medications, and infectious diseases. It is the latter that we address here.

Globally there are several infectious diseases associated with hearing loss. In children these include congenital rubella infections a direct result of bacterial meningitis infections, although with improved immunization rates these are less of a problem. In contrast Congenital cytomegalovirus infection has been on the increase.

Continuing study of Ebola, Lassa Fever and Zika point to infectious tropical diseases as another serious concern.  The large scale of infection and survisorship in Ebola outbreak in West Africa made it possible to study on a large scale reported symptoms of “post-Ebolavirus disease syndrome” (PEVDS) that include, “chronic joint and muscle pain, fatigue, anorexia, hearing loss, blurred vision, headache, sleep disturbances, low mood and short-term memory problems.” A study of 277 Ebola Survivors in one Sierra Leone community found the following clinical sequelae were common: arthralgias (76%), new ocular symptoms (60%), uveitis (18%), and auditory symptoms (24%).

Lassa Fever has unfortunately made a strong showing in West Africa this dry season. Mateer and colleagues noted an association between Lassa fever (LF) and sudden-onset sensorineural hearing loss (SHNL) was confirmed clinically in 1990. Their literature review found that, “Although LF-induced SNHL has been documented, the prevalence and economic impact in endemic regions may be underestimated.”

Finally, while much of the focus on the complications of Zika have focused on microcephaly, other problems occur.  Zare Mehrjardi et al. documented that Zika Virus may cause “other central nervous system abnormalities such as brain parenchymal atrophy with secondary ventriculomegaly, intracranial calcification, malformations of cortical development (such as polymicrogyria, and lissencephaly-pachygyria), agenesis/hypoplasia of the corpus callosum, cerebellar and brainstem hypoplasia, sensorineural hearing-loss, and ocular abnormalities as well as arthrogryposis in the infected fetuses.”

The benefits of vaccines for rubella and meningitis should spur on immunization research for Ebola, Zika and Lassa Fever. In the meantime there are some preventive measures. One would not have thought that using personal protective equipment by health workers would protect hearing, but it is a practice that should be enabled and encouraged for multiple reasons. Household and community control of Aedes aegypti and rodent breeding to prevent Zika and Lassa, respectively, can also help. By protecting our communities from infection we can also protect their hearing.

Twice a year students in the Johns Hopkins Bloomberg School of Public Health write blog postings as part of the course “Social and Behavioral Foundations of Primary Health Care.” We often share blog posts that relate to tropical health issues.  Below is a posting by class members Linda Cho, Linda Chyr, Rebecca Earnest, and Sarah Rosenberg on Zika, family planning, and reproductive health in Brazil.

In the 1960s, the Brazilian government adopted a laissez-faire attitude, which lead to the predominance of private organizations in the provision of family planning services. Since then, Brazil has witnessed one of the most dramatic reductions in family size in modern history in part due to increased access to family planning services. (Photo New York Times: Members of the Union of Mothers of Angels.)

However, in early 2015, the widespread epidemic of the Zika fever caused by the Zika virus in Brazil caused persisting gaps in access to contraception to resurface. Since it was first detected it has instilled fear and uncertainty in pregnant women whose fetuses could be at risk of Zika-related birth defects like microcephaly should the virus be contracted during pregnancy. This makes access to comprehensive reproductive health services and education a critical need for women who are pregnant or considering becoming pregnant.

While contraceptive use is fairly high in Brazil with 75.2% of women using modern forms of contraception, barriers to access remain. Some women face challenges, some of which include but are not limited to incomplete insurance coverage or lack of reimbursement for long-acting reversible contraceptives (LARCs), high up-front costs, low number of contraceptive service sites, and/or a lack of supply of the implants in the public sector . This may be one driver behind why LARCs only make up 0.5% of all contraceptive sales. Furthermore, 55% of all pregnancies in Brazil estimated to be unplanned and 20% of all lives births are attributed to teenage girls, indicating that there may be substantial reproductive knowledge gaps  in how to effectively prevent pregnancy.

Amid the spread of a virus that poses unique health risks to pregnant women and their fetuses, there is an urgent need to address these gaps in reproductive health access and education. First, the Brazilian National Health System, which laudably provides most contraceptives free of charge to about 74% of the population, needs to reevaluate existing policies that may be still limiting access to contraceptive services. Secondly, organizations like the Brazilian Society for Family Welfare (BENFAM), which provides reproductive health services and education to underserved Brazilian communities, need greater financial and political support from policymakers, civil society, and even organizations traditionally opposed to such services like the Catholic Archdiocese.

Despite Brazil’s great strides to improve access to contraception and reproductive health education in recent years, Zika’s arrival highlighted gaps in the existing system that must be addressed through policy reform and greater political and financial support. Especially in the time of Zika, Brazilian women deserve no less.

The Following blog from the 65th American Society of Tropical Medicine and Hygiene Annual Meeting opening keynote address has been re-posted here.

From moving quickly to train heads of state in risk communications, to making major decisions based on limited evidence, to sitting with Zika victims whose children had just been diagnosed with microcephaly, the head of the Pan American Health Organization (PAHO) offered a detailed assessment Sunday night of her experience with the sudden explosion of the Zika virus in the Americas.

In her keynote address to a packed hall at opening of ASTMH 2016 Annual Meeting, PAHO Director Dr. Carissa F. Etienne, MBBS, MSc, described the extraordinary experience and lessons learned from encounters with a once-obscure disease that now has been documented in 48 countries and territories in the Americas—and 67 globally.

Dr. Etienne credited “vigilant, astute, front-line health care workers” with first noting the unusual clusters of rash disease in Brazil in late 2014 that turned out to be an early indication that Zika virus had arrived. She noted it was also front-line health workers who first noted the spike in cases of microcephaly and Guillain-Barré Syndrome and connected them to the Zika virus.

Dr. Etienne said their “astute” observations have re-enforced her conviction that, when it comes to protecting the public from infectious disease, there is no substitute for “good clinical judgment and alertness for atypical events.”

Dr. Etienne recalled how quickly the situation escalated and the challenges this presented on a day-to-day basis. For example, heads of state wanted to take charge of discussing the emergency in radio and television appearances. So PAHO moved quickly to provide technical information along with training in risk communications.

There was also the fact that Zika was first discovered while many countries in the Americas were in the middle of preparing for potential Ebola infections and responding to outbreaks of chikungunya. Yet despite this confusing swirl of activity, she said health officials had to move swiftly to declare Zika an emergency, even though they lacked a complete picture of the true extent of the threat.

“Determination of causality needs to run its course, but PAHO cannot wait until the final verdict of the scientific community,” Dr. Etienne said. “We must be willing to make decisions based on incomplete evidence.”

Dr. Etienne said her experience with the Zika response has reminded her of the many ways infectious diseases take their toll on people, communities and countries. She said Zika has been particularly hard on countries in the Americas that already were suffering economically. And she said it was profoundly moving to spend time with parents whose children have been diagnosed with microcephaly linked to Zika.

“It was quite emotional,” she said. “Here are mothers and fathers loving their child and caring for their child but recognizing that this child’s life will probably be marked by disability.”

Dr. Etienne said that given limitations with diagnostic tests and disease surveillance, the current case count probably underestimates the true magnitude of Zika infections in the Americas. She also believes that “microcephaly is merely the tip of the iceberg” and it will take years to assess the full impact of Zika on children whose mothers were infected with Zika during pregnancy.

Among other things, Dr. Etienne said the experience with the Zika outbreak should prompt a re-thinking “of our approach to reproductive health services.”

“There is still a long way to go with Zika,” she said. “This is not going to be a 100 meter dash. This is a marathon in which science and public health must work hand in hand.”