Posts or Comments 19 March 2024

Archive for "Trachoma"



Elimination &MDA &NTDs &poverty &Schistosomiasis &Trachoma &Vector Control Bill Brieger | 13 Jun 2023

Eliminating NTDs as a Public Health Problem May Not Be Enough

The concept and goal of eliminating a disease appears simple on the surface, but complications ensue when the words “as a public health problem” are added.  We know that the distinction exists between eradication and elimination with the former being globally and the latter being nationally or regionally. The sum total action of eliminating a disease from all endemic countries therefore results in total global eradication.

The challenge comes when we try to qualify the concept of elimination. The US CDC defined elimination of disease as, “Reduction to zero of the incidence of a specified disease in a defined geographical area as a result of deliberate efforts; continued intervention measures are required.” Thus, there is no more transmission.  Following from this eradication is defined as, “Permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed.” Penn Medicine summarized this as, “Elimination means stopping the transmission of a disease in a specific geographic area or country, but not worldwide. Elimination is a crucial step in the path toward eradication, requiring constant monitoring and interventions to keep serious diseases at bay.”

The foregoing definitions seem straightforward, but what does elimination as a public health problem or a disease of public health concern mean? The World Health Organization recently “congratulate(d) Benin and Mali for eliminating trachoma as a public health problem. Concerning another neglected tropical disease (NTD), lymphatic filariasis (LF), global control programs are aiming “to reduce the prevalence of infection below target thresholds and to alleviate the suffering of people affected by lymphoedema and hydrocele.” Wiegand and colleagues in The Lancet Global Health note that, “For schistosomiasis, the criterion for elimination as a public health problem (EPHP) is defined as less than 1% prevalence of heavy-intensity infections (ie, ?50 Schistosoma haematobium eggs per 10 mL of urine or ?400 Schistosoma mansoni eggs per g of stool).” They take issue with the fact that such definitions mean that morbidity still exists, though at very levels, so elimination of transmission has not really occurred for any of these NTDs.

Because the social, environmental, and behavioral conditions that favor transmission may still exists, one cannot guarantee that incidence such diseases may not increase again. All three diseases, LF, Schistosomiasis, and Trachoma have been tackled primarily through preventive chemotherapy, is simply put, using mass drug administration (MDA) over a period of years until active surveillance determines that “infection (is) below target thresholds.” Trachoma does have its SAFE strategy which includes water, sanitation and hygiene interventions, but drugs can reduce the disease without long term achievements in such activities have become sustainable.

Prada et al. in the Journal of Infectious Diseases warn that there can be resurgence of a disease that was documented to be eliminated as a public health problem. They explain that the transmission assessment survey held after several MDA rounds for LF may not be enough to guarantee that low levels of transmission and eventual elimination are achieved. They conclude that, “The risk of resurgence after achieving current targets is low and is hard to predict using just current prevalence. Although resurgence is often quick (<5 years), it can still occur outside of the currently recommended post-intervention surveillance period of 4–6 years,” and recommend monitoring beyond this period.

Toor and co-researchers suggest for NTD programs that, “as case numbers drop and elimination comes into prospect, transmission reduction through other interventions, such as vector control and sanitation, becomes crucial in reducing the probability and speed of resurgence, particularly when MDA or screening programs are halted. Surveillance activities for detecting elimination and resurgence become increasingly important to ensure that successes are maintained.”

Ultimately, unless the context of NTD transmission is addressed, elimination will be an elusive goal. Therefore, as WHO advocated on the recent World NTD Day, “Everybody, including leaders and communities, to confront the inequalities that drive NTDs and to make bold, sustainable investments to free the world’s most vulnerable communities affected by NTDs from a vicious cycle of disease and poverty.”

Elimination &Health Systems &NTDs &Polio &Surveillance &Trachoma Bill Brieger | 29 May 2022

When is Disease Elimination not Elimination?

A May 28th press release from the World Health Organization states that, “Togo eliminates trachoma as a public health problem.” The article explains that …

Validation of trachoma elimination as a public health problem in Togo was based on evidence. Several population-based trachoma surveys were conducted starting from 2006 to 2017. The 2017 survey using WHO recommended methodology found that the prevalence of key indicators was below the WHO trachoma elimination threshold. There was also evidence that Togo’s health system is able to identify and treat new cases of late complications of trachoma.

This raises the question, is Trachoma gone from Togo or does trachoma continue to exist at some low level whereby, as WHO notes, Togo has joined, “12 other countries that have been validated by WHO for having eliminated trachoma as a public health problem.”

This description of disease elimination contrasts sharply with the global concerns when “health authorities in Malawi have declared an outbreak of wild poliovirus type 1 after a case was detected in a young child in the capital Lilongwe. This is the first case of wild poliovirus in Africa in more than five years.” Wild polio virus had been declared eliminated in Africa, and just one case in one country grabs international attention.

Would one case of trachoma tomorrow receive the same concern in Togo? Apparently not according to the WHO definition, “Elimination of trachoma as a public health problem is defined as: (i) a prevalence of trachomatous trichiasis (TT) “unknown to the health system” of < 1 case per 1000 total population; and (ii) a prevalence of trachomatous inflammation-follicular (TF) in children aged 1–9 years of < 5%, in each formerly endemic district.”

So, while no cases of smallpox, guinea worm or polio would be tolerated after elimination has been declared, parents of a child who develops trachoma in Togo tomorrow would be told that your child’s case is only 1 in a 1000 and not of concern to public health. The caveat is though that “the health system (must be) able to identify and manage incident TT cases.” Presumably, if such management capacity does not exist, the disease in question could spread and elimination would be eliminated.

Another Neglected Tropical Disease, Lymphatic Filariasis, faces the same challenge in terms of elimination status. WHO explained in its guidance that, “In 1997, the 50th World Health Assembly resolved to eliminate LF as a public-health problem (resolution WHA50.29). In response, WHO proposed a comprehensive strategy for achieving the elimination goal that included interrupting transmission in endemic communities and implementing interventions to prevent and manage LF-associated disabilities The LF guidance stresses “Effective monitoring, epidemiological assessment and evaluation are necessary to achieve the aim of interrupting LF transmission,” or in a word Surveillance. There is clear concern for “absence of transmission” and worries about “recrudescence.”

While polio has a vaccine and guinea worm relies on providing safe community water, LF and Trachoma elimination depends on mass drug administration (MDA) at planned intervals until such time as transmission is reduced. All require a strong health system to implement, but the challenges of maintaining MDAs until such time as elimination has been validated is somewhat more challenging. In this context the communication is extremely important. Just because WHO validates the elimination of a disease as a public health problem, does not give policy makers license to ignore that disease. Advocacy is continually needed such that even after apparent elimination, neglected diseases will not be forgotten and health systems themselves not neglected.

Diagnosis &Elimination &Environment &Health Information &Health Systems &History &Invest in Malaria Control &Microscopy &Surveillance &Trachoma Bill Brieger | 10 Sep 2020

Malaria News Today 2020-09-10

These malaria and related news and abstracts stress the importance of sentinel surveillance systems, strong political and systems commitment to disease elimination, malachite green loop-mediated isothermal amplification for better malaria detection, and the threat of neglected fungal infections. An article from The Lancet shows that it is not just money that is needed to eliminate malaria, but better management and systems. Finally a bit of history from 18th Century North Carolina is shared. Click the links in each section to learn more about each topic.

Implementation of a malaria sentinel surveillance system in Togo: a pilot study

Since July 2017, 16 health facilities called sentinel sites, 4 hospitals and 12 peripheral care units located in 2 epidemiologically different health regions of Togo, have provided weekly data on malaria morbidity and mortality for the following 3 target groups:?<?5-years-old children,???5-years-old children and adults, and pregnant women. Data from week 29 in 2017 to week 13 in 2019 were analysed.

Each sentinel site provided complete data and the median time to data entry was 4 days. The number of confirmed malaria cases increased during the rainy seasons both in children under 5 years old and in children over 5 years old and adults. Malaria-related deaths occurred mainly in children under 5 years old and increased during the rainy seasons. The mean percentage of tested cases for malaria among suspected malaria cases was 99.0%. The mean percentage of uncomplicated malaria cases handled in accordance with national guidelines was 99.4%. The mean percentage of severe malaria cases detected in peripheral care units that were referred to a hospital was 100.0%. Rapid diagnostic tests and artemisinin-based combination therapies were out of stock several times, mainly at the beginning and end of the year. No hospital was out of stock of injectable artesunate or injectable artemether.

These indicators showed good management of malaria cases in the sentinel sites. Real-time availability of data requires a good follow-up of data entry on the online platform. The management of input stocks and the promptness of data need to be improved to meet the objectives of this malaria sentinel surveillance system.

Evaluation of the colorimetric malachite green loop-mediated isothermal amplification (MG-LAMP) assay …

… for the detection of malaria species at two different health facilities in a malaria endemic area of western Kenya. Prompt diagnosis and effective malaria treatment is a key strategy in malaria control. However, the recommended diagnostic methods, microscopy and rapid diagnostic tests (RDTs), are not supported by robust quality assurance systems in endemic areas. This study compared the performance of routine RDTs and smear microscopy with a simple molecular-based colorimetric loop-mediated isothermal amplification (LAMP) at two different levels of the health care system in a malaria-endemic area of western Kenya.

Patients presenting with clinical symptoms of malaria at Rota Dispensary (level 2) and Siaya County Referral Hospital (level 4) were enrolled into the study after obtaining written informed consent. Capillary blood was collected to test for malaria by RDT and microscopy at the dispensary and county hospital, and for preparation of blood smears and dried blood spots (DBS) for expert microscopy and real-time polymerase chain reaction (RT-PCR).

Results of the routine diagnostic tests were compared with those of malachite green loop-mediated isothermal amplification (MG-LAMP) performed at the two facilities.
A total of 264 participants were enrolled into the study. At the dispensary level, the positivity rate by RDT, expert microscopy, MG-LAMP and RT-PCR was 37%, 30%, 44% and 42%, respectively, and 42%, 43%, 57% and 43% at the county hospital. Using RT-PCR as the reference test, the sensitivity of RDT and MG-LAMP was 78.1% (CI 67.5–86.4) and 82.9% (CI 73.0–90.3) at Rota dispensary.

At Siaya hospital the sensitivity of routine microscopy and MG-LAMP was 83.3% (CI 65.3–94.4) and 93.3% (CI 77.9–99.2), respectively. Compared to MG-LAMP, there were 14 false positives and 29 false negatives by RDT at Rota dispensary and 3 false positives and 13 false negatives by routine microscopy at Siaya Hospital. MG-LAMP is more sensitive than RDTs and microscopy in the detection of malaria parasites at public health facilities and might be a useful quality control tool in resource-limited settings.

Terminating Trachoma. How Myanmar eliminated blinding trachoma.

Download the book  from WHO New Delhi: World Health Organization, Regional Office for South-East Asia; 2020. Licence: CC BY-NC-SA 3.0 IGO.  Myanmar’s three-phase approach to eliminating trachoma has been a great success, which will certainly continue. The country’s visionary National Eye Health Plan 2017-2021, which is closely aligned with international policies for prevention of blindness, gives confidence that Myanmar will maintain its elimination status. This book chronicles how a combination of good leadership, effective partnerships, health-care facilities and hardworking health-care personnel helped Myanmar eliminate trachoma as a public health problem.

Health sector spending and spending on HIV/AIDS, tuberculosis, and malaria, and development assistance for health, SDG Progress

Although the progress towards Sustainable Development Goal (SDG) 3, which aims to “ensure healthy lives and promote well-being for all at all ages”, has been assessed in various works, there is less research focusing on tracking spending towards this goal. In this study, spending estimates were used to determine progress in financing the priority areas of SDG3, examine the correlation between outcomes and financing, and identify where resource gains are most required to attain the SDG3 indicators for which data are available.

From 1995 to 2017, domestic health spending was determined, disaggregated by source (government, out-of-pocket, and prepaid private) for 195 countries and territories. Outcomes suggest a global rise in total health spending since the state of the SDGs in 2015, reaching $7·9 trillion (7·8–8·0) in 2017, and is estimated to rise to $11·0 trillion (10·7–11·2) by 2030, although with substantial disparity across countries. Per estimates, low-income and middle-income countries, in 2017, had an estimated spending of $20·2 billion on HIV/AIDS, $10·9 billion on tuberculosis, and $5·1 billion on malaria in endemic countries.

Although there is an increase in both domestic government and DAH spending, across these three diseases, variation in the accompanied changes in outcomes was observed. Malaria was noted to have the most consistent reductions in outcomes across countries as spending has raised. Findings thereby suggest mixed progress towards meeting the SDG3 targets; the progress varied by country and by target. The evidence on the scale-up of spending and improvements in health outcomes suggest a nuanced relationship, such that outcomes do not always improve with increases in spending.

Although more resources may be required by the countries to achieve SDG3, there will also be a necessity for addressing other constraints in the broader health system such as inefficient allocation of resources across interventions and populations, weak governance systems, human resource shortages, and drug shortages.

Ignored fungal infections kill more people annually than HIV and malaria combined

Carolina Pohl-Albertyn says that, “You may also know that there are other infections causing great concern, such as HIV (690 000 deaths/year), tuberculosis (1.5-million deaths/year), and malaria (405,000 deaths/year). But what would be your reaction if you knew that fungal infections (ranging from skin and mucosal infections (e.g. vaginal or oral thrush) to deadly systemic and organ infections (e.g. candidiasis, cryptococcal meningitis, and bronchopulmonary aspergillosis]) affect more than one-billion people each year, of which more than 150-million cases are severe and life-threatening and cause 1.7 million deaths per year?”

Malaria was once scourge in Chowan County, North Carolina

Nicole Bowman-Layton (Editor) provides some history of malaria. It’s fascinating to think that less than 100 years ago this disease was still a major scourge in Chowan County. I’ve wanted to write about this topic for a long time since the coronavirus popped up but was a bit concerned about writing about a somewhat depressing topic.

According to NCPedia malaria came to North Carolina in the 1500s from some of the first European explorers who were bitten by our friendly Anopheles mosquitoes and then transmitted to the native population. And as we well know, we live in a very damp environment surrounded by sitting water which certainly increases the harvest of mosquitos. Some of the most prominent Revolutionary Edentonians suffered from the “Ague” during their lives. Declaration signer Joseph Hewes suffered from “intermittent fever and ague” throughout his life which were certainly symptoms of malaria.

The German traveler Dr. Johan Schoepf wrote in his book Travels in the Confederation, 1783-1784, of “…the sickliness of the inhabitants, especially prevalent in the low, overflowed, and swampy parts of this country, and giving the people a pale, decayed, and prematurely old look. This is the case not only about Edenton, but along the entire low-lying coast, which this fall, from Virginia to South Carolina, was visited with numerous fevers.

COVID-19 &Diagnosis &Ebola &Malaria in Pregnancy &MDA &NTDs &Trachoma &Zoonoses Bill Brieger | 08 Sep 2020

Malaria News Today 2020-09-08

Today we share news and abstracts concerning detecting malaria in pregnancy, news about the opening remarks from the WHO Director General at a special malaria and COVID-19 webinar, resumption of NTD activities after COVID-19 restrictions reduced, and mapping of Ebola carrying bats whose territory overlaps malaria in Africa. Click on the links to read more.

Prevalence and clinical impact of malaria infections detected with a highly sensitive HRP2 rapid diagnostic test in Beninese pregnant women

While sub-microscopic malarial infections are frequent and potentially deleterious during pregnancy, routine molecular detection is still not feasible. This study aimed to assess the performance of a Histidine Rich Protein 2 (HRP2)-based ultrasensitive rapid diagnostic test (uRDT, Alere Malaria Ag Pf) for the detection of infections of low parasite density in pregnant women.

This study demonstrates the higher performance of uRDT, as compared to cRDTs, to detect low parasite density P. falciparum infections during pregnancy, particularly in the 1st trimester. uRDT allowed the detection of infections associated with maternal anaemia.

The distribution range of Ebola virus carriers in Africa may be larger than previously assumed

Since Ebola overlaps both symptomatically and geographically with malaria in Africa, it is “Worrying that science has hitherto underestimated the range of Ebola-transmitting bat and fruit bat species. In this case, the models would provide a more realistic picture,” explains Dr. Lisa Koch

Based on ecological niche modeling, his team was able to show that the respective bat and fruit bat species are able to thrive in West and East Africa, including large parts of Central Africa. A wide belt of potential habitats extends from Guinea, Sierra Leone, and Liberia in the west across the Central African Republic, the Republic of the Congo and the Democratic Republic of the Congo to Sudan and Uganda in the East. A few of the studied bats and fruit bats may even occur in the eastern part of South Africa.

WHO Director-General’s Opening Remarks At the Webinar – Responding to the Double Challenge of Malaria and Covid-19

The WHO Director General is encouraged by efforts to maintain malaria services despite the COVID-19 outbreak, but says, “I would like to recognize and applaud all these efforts, and to thank all of you who have worked so hard to preserve and maintain those services to the greatest degree possible. However, despite these actions, it breaks my heart to report that we still expect to see an increase in cases and deaths from malaria.

“In a recent WHO survey of 105 countries, 46% of countries reported disruptions in malaria diagnosis and treatment. These disruptions threaten to set us back even further in realizing our shared vision for a malaria-free world.”

NTD Disease treatments restart in Africa as COVID-19 restrictions ease

It is not just malaria services that have been disrupted by COVID-19 responses. Treatment programmes that will reach millions of Africans at risk from debilitating neglected tropical diseases (NTDs) have restarted in a significant step towards COVID-19 recovery. Around one million people in Jigawa state, Nigeria have received antibiotics to treat the blinding eye disease trachoma and stop it from spreading.

Nigeria is the first country that Sightsavers and partners has supported to resume work on NTDs, which can have a devastating impact on some of the poorest communities in the world, with other African countries due to follow soon. In April, the threat of COVID-19 led the World Health Organization to recommend suspending mass treatment campaigns, which treat and prevent these diseases, but it has since provided guidance on restarting activities safely.

Borders &Diagnosis &Ebola &Elimination &Integrated Vector Management &ITNs &Mosquitoes &NTDs &Snakebite &Trachoma &Urban Bill Brieger | 04 Aug 2019

Tropical Health Update 2019-08-04: Ebola, Malaria Vectors, Snakebite and Trachoma

In the past week urban transmission in Goma, a city of at least 2 million inhabitants in eastern Democratic republic of Congo, was documented as a gold miner came home and infected his wife and child. To get a grip on the spread of the disease, DRC is considering another vaccine, not without some controversy. WHO provides detailed guidance on all aspects of response. On the malaria front we have learned more about malaria vectors, natural immunity and reactive case detection.

Ebola Challenges: Vaccines, Urban Transmission

The current Ebola vaccine being deployed to over 150,000 people in North Kivu and Ituri Provinces was itself an experimental intervention during 2016 when it was first used in the largest ever outbreak located in West Africa. BBC reports that, “World Health Organization (WHO) data show the Merck vaccine has a 97.5% efficacy rate for those who are immunised, compared to those who are not.”

The proposed addition of a Johnson and Johnson vaccine would be in that same experimental phase if introduced in DRC now. It has been proven safe as well as effective in other primates. The challenge is that even though the Merck vaccine supplies are near 500,000, this is not enough to cover the potential needs in an area with over 10 million people, although Merck is still producing more. At present, BBC says, “Those pushing for the use of the new Johnson & Johnson vaccine, had proposed using it to create a protective wall, vaccinating people outside the outbreak zone.” In addition, the new national response team is concerned that “Only about 50% of cases of Ebola in the Democratic Republic of Congo are being identified.”

Finally, there is the issue of community mistrust of government workers and challenging logistics. “There are also concerns that the new vaccine – which requires two injections 56 days apart – may be difficult to administer in a region where the population is highly mobile, and insecurity is rife.”

If efforts at vaccination are needed soon in Goma, up to 2 million doses might be needed. Reuters reports that, “Congolese authorities were racing to contain an Ebola epidemic on Thursday, after a gold miner with a large family contaminated several people in the east’s main city of Goma before dying of the hemorrhagic fever.” Readers may recall that the West Africa outbreak of 2014-16 in Guinea, Sierra Leone and Liberia accelerated greatly after infected people went to major cities in search of help.

The miner is the second ‘imported case into Goma, which borders Rwanda, but because his family lives there, he has already infected his wife and one of his 10 children. Contacts are being traced and monitored, but this urban and border threat is one of the factors that led WHO to finally declare the current outbreak a public health emergency.

Malaria

As we move toward malaria elimination Reactive Case Detection (RCD) has been proposed as an integral part of these efforts with the hopes that is can be conceived of as a way of gradually decreasing transmission, according to an article in Malaria Journal. In fact, the value of RCD may be limited as follows:

  • RCD alone can eliminate malaria in only a very limited range of settings, where transmission potential is very low
  • In other settings, it is likely to reduce disease burden and help maintain the disease-free state in the face of imported infections

Another article looks at “natural exposure to gametocytes that can result in the development of immunity against the gametocyte by the host as well as genetic diversity in the gametocyte.” The researchers learned that there can be variations in immune response depending on season and geography. This information is helpful in planning malaria elimination interventions.

On the vector front a baseline susceptibility testing was conducted in 16 countries in sub-Saharan Africa for neonicotinoids. “The target site of neonicotinoids represents a novel mode of action for vector control, meaning that cross-resistance through existing mechanisms is less likely.” The findings will help in the preparation for rollout of clothianidin formulations as part of national IRS rotation strategies by PMI and other partners.

Researchers also called on us to learn more about malaria vectors in other parts of the world. In order to eliminate Plasmodium falciparum from the Caribbean and Central America program planners should consider local vector characteristics such as An. albimanus. They found that, “House-screening and repellent IRS are potentially highly effective against An. albimanus if people are indoors during the evening.”

Vectors are also of concern on the edges of malaria transmission, particularly in South Africa, one of the ‘elimination eight’ countries of the Southern Africa Development Community. Researchers examined the, “potential role of Anopheles parensis and other Anopheles species in residual malaria transmission, using sentinel surveillance sites in the uMkhanyakude District of northern KwaZulu-Natal Province.” They found Anopheles parensis is a potential but minimal vector of malaria in South Africa “owing to its strong zoophilic tendency.” On the other hand, An. arabiensis was found to be the major vector responsible for residual malaria transmission in South Africa. Since these mosquitoes were found in outdoor-placed resting traps, interventions are needed to control outdoor-resting of vector populations.

NTDs of Concern

During the week, the member states of the African Union renewed their commitment to fight and permanently eliminate Neglected Tropical Diseases. Africa.com reported that, “Achievements to date include 1 billion people treated against at least one NTD and 37 countries have completed the removal of at least one NTD.”

Although some reports have discounted the idea of trachoma in Namibia, there may be reason to re-examine the situation. On Twitter Anthony Solomon notes that Namibia needs #trachoma prevalence surveys. A just-completed joint Ministry of Health & Social Services/@WHO mission found active trachoma & trichiasis in Zambezi & Kunene Regions.

The Times of India draws attention to snakebite. It says that “Under-reported and inadequately treated, fatalities in India are estimated at close to 50,000 a year, the world’s highest.”

Overall we can see that the concept of ‘neglect’ has several uses. There is neglect if half of Ebola cases are undetected. There is neglect if we do not understand malaria vectors in low transmission areas. Finally, there is neglect if we do not conduct up-to-date disease surveys to determine whether a disease is present or not. Elimination of tropical diseases is challenging when key processes are neglected.