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CSU 16/2009: COCHRANE REVIEW ON IMPACT OF INSECTICIDE TREATED NETS IN PREGNANT WOMEN

Monday, 17th of May 2010

CSU 16/2009: COCHRANE REVIEW ON IMPACT OF INSECTICIDE  TREATED  NETS IN PREGNANT WOMEN/ CENTENARY OF CHAGAS' DISCOVERY OF CHAGAS DISEASE
 
 1) COCHRANE REVIEW, NET IMPACT IN PREGNANT WOMEN
 
 This just updated Cochrane review looks at the impact of insecticide
 treated nets for malaria prevention in pregnant women, especially in
 Sub-Saharan Africa. 'ITNS have a beneficial impact on pregnancy outcome in
 malaria-endemic regions of Africa when used by communities or individual
 women.(summary, below).'
 
 Taken together with previous reviews of net impact in under-fives, this
 review presents us with one of those interventions which has a well
 documented impact both towards achievement of MDG4 and MDG 5.
 
 Neither the present review nor previous ones should slow the progress of
 current moves towards universal LLIN coverage of all sleeping places in
 highly malarious communities. On the contrary, universal LLIN coverage
 reduces the risks to low risk populations, to pregnant women, and to
 under-five children.
 
 Scroll down to 2) for a look at the life and work of Carlos Chagas.
 
 Good reading.
 BD
 
 To subscribe or unsubscribe from this list, pls contact Evelyn Chege,
 echege@unicef.org
 
 PS Readers interested in viewing other Cochrane reviews can consult the
 homepage at www.cochrane.org
 Insecticide-treated nets for preventing malaria in pregnancy
 
 
 Gamble CL, Ekwaru JP, ter Kuile FO
 
 
 Summary
 Insecticide-treated nets for preventing malaria in pregnancy
 
 
 In endemic areas, malaria in pregnancy is a major public health problem. It
 contributes to severe anaemia in the mother and low birth weight for
 babies, which are associated with poor infant health and early infant
 death. Also the unborn child and the pregnant woman may die from malaria in
 pregnancy. Protection with insecticide-treated bednets (ITNs) during
 pregnancy is widely advocated, but evidence of their benefit has been
 inconsistent. This review found five trials of ITNs in pregnant women. The
 four trials in sub-Saharan Africa compared ITNs with no nets and showed a
 benefit from ITNs in terms of fewer malaria infections, low birthweight
 babies, and fewer babies died before delivery. The effects on severe
 anaemia in the mothers were inconclusive. The one trial from Asia compared
 ITNs with untreated nets and showed a beneficial effect on anaemia in women
 and fewer babies died before delivery, but it had no impact on other
 outcomes. ITNs have been shown to be beneficial and should be included in
 strategies to try to reduce the adverse effects of malaria in pregnant
 women in endemic areas of the world.
 
 
 This is a Cochrane review abstract and plain language summary, prepared and
 maintained by The Cochrane Collaboration, currently published in The
 Cochrane Database of Systematic Reviews 2009 Issue 1, Copyright © 2009 The
 Cochrane Collaboration. Published by John Wiley and Sons, Ltd.. The full
 text of the review is available in The Cochrane Library (ISSN 1464-780X).
 This record should be cited as: Gamble C, Ekwaru JP, ter Kuile FO.
 Insecticide-treated nets for preventing malaria in pregnancy. Cochrane
 Database of Systematic Reviews 2006, Issue 2. Art. No.: CD003755. DOI:
 10.1002/14651858.CD003755.pub2.
 
 
 Abstract
 Background
 
 
 Malaria in pregnancy is associated with adverse consequences for mother and
 fetus. Protection with insecticide-treated nets (ITNs) during pregnancy is
 widely advocated, but evidence of their benefit has been inconsistent.
 
 
 Objectives
 
 
 To compare the impact of ITNs with no nets or untreated nets on preventing
 malaria in pregnancy.
 
 
 Search strategy
 
 
 We searched the Cochrane Infectious Diseases Group Specialized Register
 (January 2006), CENTRAL (The Cochrane Library 2005, Issue 4), MEDLINE (1966
 to January 2006), EMBASE (1974 to January 2006), LILACS (1982 to January
 2006), and reference lists. We also contacted researchers working in the
 field.
 
 
 Selection criteria
 
 
 Individual and cluster randomized controlled trials of ITNs in pregnant
 women.
 
 
 Data collection and analysis
 
 
 Three authors independently assessed the risk of bias in the trials and
 extracted data. Data were combined using the generic inverse variance
 method.
 
 
 Main results
 
 
 Six randomized controlled trials were identified, five of which met the
 inclusion criteria: four trials from sub-Saharan Africa compared ITNs with
 no nets, and one trial from Asia compared ITNs with untreated nets. Two
 trials randomized individual women and three trials randomized communities.
 In Africa, ITNs, compared with no nets, reduced placental malaria in all
 pregnancies (risk ratio (RR) 0.79, 95% confidence interval (CI) 0.63 to
 0.98). They also reduced low birthweight (RR 0.77, 95% CI 0.61 to 0.98) and
 fetal loss in the first to fourth pregnancy (RR 0.67, 95% CI 0.47 to 0.97),
 but not in women with more than four previous pregnancies. For anaemia and
 clinical malaria, results tended to favour ITNs, but the effects were not
 significant. In Thailand, one trial randomizing individuals to ITNs or
 untreated nets showed a significant reduction in anaemia and fetal loss in
 all pregnancies but not for clinical malaria or low birthweight.
 
 
 Authors' conclusions
 
 
 ITNs have a beneficial impact on pregnancy outcome in malaria-endemic
 regions of Africa when used by communities or by individual women. No
 further trials of ITNs in pregnancy are required in sub-Saharan Africa.
 Further evaluation of the potential impact of ITNs is required in areas
 with less intense and Plasmodium vivax transmission in Asia and Latin
 America.
 
 
 2)  CENTENARY OF CHAGAS' DISCOVERY OF CHAGAS DISEASE
 
 It was in April 1909 that the Brazilian researcher Carlos Chagas, aged 29,
 made discoveries of the yet unidentified Chagas' disease in a two-year-old
 girl. He named the causative agent of the disease Trypanosoma cruzei, after
 Oswaldo Cruz. The homepage of the Oswaldo Cruz Institute (see full text
 below) tells the story.
 
 ‘After several tests in human beings and animals, he found a cat with
 parasite in the bloodstream. Two or three weeks later (April 14, 1909), he
 was asked to investigate on the possibility of an acute malarial episode in
 a 2 years old girl (Berenice) living in the same house where this feline
 was found. He had previously examined this girl and no parasite could be
 observed before. However, several parasites could be detected this time.
 
 Therefore, he suggested the possibility of an acute phase of a disease yet
 to be described. Several examinations showed the disappearance of
 flagellates in the bloodstream as the symptoms vanished, thus raising the
 possibility of a chronic phase of this new disease. On April 23rd, Oswaldo
 Cruz announced Carlos Chagas' discovery at a session of the Brazilian
 National Academy of Medicine.’
 
 
 For more detail on this extraordinary man, go to the biography at
 http://en.wikipedia.org/wiki/Carlos_Chagas
 
 Good reading.
 
 BD
 
 To subscribe or unsubscribe from this list, pls contact Evelyn Chege at
 echege@unicef.org
 
 HISTORICAL ASPECTS
 
 By: Silvano Wendel and Zigman Brener (in: Chagas Disease - American
 Trypanosomiasis: its impact on transfusion and clinical medicine. S.
 Wendel, Z. Brener, M.E. Camargo, A. Rassi (Edt.). ISBT BRAZIL'92, SAO
 PAULO,
 BRAZIL).
 
 Carlos Justiniano Ribeiro Chagas was born on July 9th , 1879 in Oliveira,
 in a coffee farm in the State of Minas Gerais. His father (Jose Justiniano
 das Chagas) died when he was only 4 years old, leaving his mother (Mariana
 Candida Chagas) the difficult task to raise four young children.
 
 In 1896, under the influence of his uncle (Carlos Ribeiro de Castro) he
 decided to study medicine in Rio de Janeiro. In 1900 he became assistant to
 Prof. Francisco Fajardo, dedicating his initial efforts to the control of
 malaria. In fact, his mentor convinced him to focus his graduating thesis
 on "Hematological Aspects of Malaria". He was also responsible for
 introducing Carlos Chagas to Oswaldo Cruz, who, at the time was in charge
 to develop his great work on Malaria and Yellow Fever eradication in Rio de
 Janeiro. These diseases were responsible for a great devastation of the
 local population.
 
 Furthermore, many ships from Europe and North America refused to dock in
 Rio de Janeiro harbor, jeopardizing the financial economy of the Brazilian
 capital at the turn of the century. Oswaldo Cruz became the founder of
 Manguinhos Institute (now named after his founder: Instituto Oswaldo Cruz),
 heading to major contributions for the development of Preventive and
 Sanitary Medicine in Brazil.
 
 Despite a strong friendship between Carlos Chagas and Oswaldo Cruz, Chagas
 decided not to follow his friend to Manguinhos. After a short working
 period as a general practitioner in Jurujuba, he was asked to eradicate the
 malaria epidemic which was devastating the city of Santos (1905). There,
 the Santos Docks Company was building port facilities to server the city of
 São Paulo, especially for coffee exportation. Although no long-lasting
 insecticides
 (e.g.DDT) were available at that time, Chagas focused his efforts in
 destroying anophelines mosquitoes inside homes; this became the first well
 succeeded Campaign for malaria eradication achieved in Brazil. He, then,
 returned to Rio de Janeiro, in order to fight malaria along the Xerem River
 banks, in the outskirts of Rio de Janeiro. He became a member of the
 Manguinhos Institute, where he joined famous foreign microbiologists such
 as Prowazeck and Max Hartmann.
 
 In 1908, the Brazilian Government was trying to connect Belem (in the
 Amazon Basin) to Rio de Janeiro, but construction had to be halted in Minas
 Gerais due to a severe malaria attack suffered by the railroad workers,
 near the Velhas River Valley. Oswaldo Cruz commissioned Carlos Chagas and
 Belisario Pena to that region, where they settled in Lassance their
 headquarters inside a railroad car, which served as consultation room,
 laboratory and sleeping quarters.
 
 After one year of exhausting work, Carlos Chagas was advised by a railroad
 engineer, Cantarino Mota and by Belisario Pena about the existence of a
 hematophagus bugs which, due to their typical behavior of biting human
 beings (while sleeping at night) on the uncovered face, were known as
 "barbeiros" (barbers) or "kissing bugs". As C. Chagas candidly described
 "We spent more than one year in that area, without having any notice on the
 existence of a hematophagic insect in the huts, currently known as
 barbeiro, chupão or chupança". What would have happened if Chagas had left
 this region after the malaria eradication without meeting with Cantarino
 Mota, could only be predicted by the Gods of Science.
 
 Chagas became interested in researching the possibility of this bug
 transmitting any kind of parasite to human or other vertebrates. Soon he
 detected flagellates resembling crithidiae in the hindgut of this bug.
 Intrigued by the possibility that this parasite could represent an
 evaluative stage of Trypanosoma minasense, which he had previously
 described in 1908, infesting marmosets (Callithrix), he sent some bugs to
 Manguinhos to be fed in primates free of infection. After some weeks, the
 same flagellates were recovered in the blood stream of those animals and he
 recognized a new species, different from T. minasense or "any other species
 of the same genus". The parasite was first named as Schyzotrypanum cruzi
 (in honor of Oswaldo Cruz); subsequently it was renamed as Trypanosoma
 cruzi.
 
 Carlos Chagas returned to Lassance looking for the presence of vertebrate
 hosts of this newly discovered parasite. After several tests in human
 beings and animals, he found a cat with parasite in the bloodstream. Two or
 three weeks later (April 14, 1909), he was asked to investigate on the
 possibility of an acute malarial episode in a 2 years old girl (Berenice)
 living in the same house where this feline was found. He had previously
 examined this girl and no parasite could be observed before. However,
 several parasites could be detected this time. Therefore, he suggested the
 possibility of an acute phase of a disease yet to be described. Several
 examinations showed the disappearance of flagellates in the bloodstream as
 the symptoms vanished, thus raising the possibility of a chronic phase of
 this new disease. On April 23rd, Oswaldo Cruz announced Carlos Chagas'
 discovery at a session of the Brazilian National Academy of Medicine. His
 findings were also reported as previous notes in "Brazil Medico" and
 "Archive für Schiffs und Tropen Hygiene". In August he published in the
 first volume of "Memórias do Instituto Oswaldo Cruz" his classical paper
 about a "New Human Trypanosomiasis". In this paper he described the human
 infection, parasite
 morphology in bloodstream, cycle in the digestive trait of invertebrate
 vector, cultivation in agar-blood and transmission to vertebrates of
 flagellates from infected triatomines. Although some slight errors were
 committed in relation to the parasite life cycle, the great contribution of
 this work clearly surpassed some minor mistakes.
 
 After these first observations, he returned to endemic zones to study the
 clinical stages of this disease. he described the effects on heart and
 gastrointestinal systems. Furthermore, the neurological manifestations were
 also observed by the findings of meningoencephalitis in a mortal case.
 
 Additional studies showed that the initial findings on the thyroid gland
 could not be corroborates by clinical facts and that all the wide range of
 neurological cases observed in the region could not be explained by this
 disease. He described the main cardiac disturbances such as those related
 to the degeneration of the Hiss bundle, premature beats, atrio-ventricular
 blockade, Stoke-Adams syndrome, bradicardia and congestive heart failure.
 
 In 1911, he presented at the National Academy of Medicine (Rio de Janeiro)
 the first case of a congenital case and in 1912 the possibility of a
 sylvatic cycle in armadillos.
 
 In 1916, he firstly raised that the digestive system could also be
 involved, especially the related to megaesophagus and dysphagia ("Mal do
 Engasgo" or "Swallow disease"), which had been regionally known for over a
 hundred years.
 
 The genius of Carlos Chagas enabled him to describe, when he was only 29
 years old, the agent, vectors, clinical signs in human beings, animals and
 the existence of animal reservoirs of a new disease which was now known as
 Chagas disease (a name suggested by Miguel Couto, one of his former
 teachers) or American Trypanosomiasis. Additionally, he influenced other
 fellow researchers in Manguinhos. Gaspar Vianna, described in 1911 the
 intracellular cycle (in a necropsied child who died in the acute phase) as
 "successive binary division as leishmanias with subsequent transformation
 to trypanosomes inside the cells and the evasion of this parasite to other
 cells". Arthur Neiva became very interested to study the insects and soon
 he became the best specialist in triatomines of his time. Also, Guerreiro
 and Machado introduced the method of Bordet and Gengou (Complement
 Fixation) for serological diagnosis.
 
 Chagas was declared "Extraordinary Member" of Brazilian Academy of Medicine
 and also received the Schaudinn Prize, which was awarded every four years
 to the best work in Parasitology and Tropical Medicine in the world. He was
 also conceded honorary degrees from the Universities of Buenos Aires, Lima,
 Harvard, Brussels, Hamburg, Paris and memberships in several medical
 societies. Additionally, he was granted the Great Prize of the Pasteur
 Centenary Commemorative Exposition in Strasbourg (1922).
 
 Chagas was also commissioned to control malaria in the Amazon, a task which
 clearly had a strong influence in his life when developing Preventive
 Medicine in Brazil.
 
 After the death of Oswaldo Cruz in 1917, he replaced him as director of the
 Manguinhos Institute, a position he held until his death in 1934 , with the
 difficult task of controlling the Spanish Fever in Rio de Janeiro. He died
 on November 8th, 1934 at the age of 55. His lifelong work was followed by
 several scientists in the Manguinhos Institute.
 
 His great success naturally provoked some opposition. In 1916, during the
 1st Panamerican Congress in Buenos Aires (Argentina), Krause, one of the
 most prominent German microbiologists clearly denied his findings, since he
 was unable to find cases of Chagas disease in areas such as the Argentine
 Chaco. Unfortunately, he also had opponents in the National Academy of
 Medicine and Chagas disease was forgotten for almost 20 years.
 
 From 1931 to 1936, Johnson and Rivas collected 19 cases of Chagas disease
 in Panama and Mazza in Argentina, described after 1934 more than a thousand
 cases, particularly in regions where Krause had been 20 years before and
 led him to deny the existence of American Trypanosomiasis.
 
 It is interesting to know that Berenice, the young girl who enabled Chagas
 to describe the first acute case, was found alive in 1961 at the age of 53
 and extensively studied in Belo Horizonte, clearly demonstrating that
 Chagas disease may remain for more than 50 years as a chronic human
 disease. At that time she only had a positive Complement Fixation Test and
 T. cruzi could be isolated from the bloodstream by xenodiagnosis, though no
 cardiac, digestive or other clinical manifestations could be found.
 
 The possibility of Transfusion Transmitted Chagas disease (TxCD) was first
 raised by Mazza in 1936, followed by Dias I Brazil (1945), Bacigalupo in
 Argentina (1945) and Talice in Uruguay (1947).
 
 In the 40's, the Argentine Sanitary code stated that donors who "could
 suffer from Syphilis, Recurrent Fever, infectious jaundice, Tuberculosis,
 Leprosy, Nicholas-Favre, Malaria, Leishmaniasis, Trypanosomiasis or any
 other diseases whose agent lives or circulates in the bloodstream, should
 be rejected, showing how long TxCD has been a major concern.
 
 Blood donors found to be reactive by Complement Fixation Tests were first
 described in 1949 in Belo Horizonte (Brazil), followed in São Paulo in
 1951.
 
 The first reported cases of TxCD were in São Paulo, in 1952 by Pedreira de
 Freitas. At the same time this author started to work on chemoprophylaxis
 of whole blood, which led to the description of Gentian Violet as an useful
 agent by Nussenzweig (1953). Further cases of TxCD were described in
 Brazil, Argentina, Venezuela, Chile, Bolivia and gradually in all Latin
 American countries. Recently, three cases have been reported in North
 America, one in
 Canada and two in USA.
 
 Although complement fixation tests were described for Chagas disease since
 1913, and xenodiagnosis in 1914, a great development in serodiagnosis of
 Chagas disease occurred after 1970 (see chapter 10).
 
 In Brazil (where the majority of cases of TxCD were described), paid donors
 were progressively abandoned since 1980. Additionally, two main events led
 to a positive effect on blood transfusion: the setting of a National Policy
 on Blood Products and the newly described disease - AIDS - which promptly
 changed Blood Transfusion scenario in Brazil. Although many things remain
 to be done in this vast area of Latin America, including Brazil, there are
 no
 doubts that Blood Transfusion is now facing a major development.
 
 However, the economical and political turmoil which faced (and in certain
 areas are still facing) the majority of Latin American countries led to a
 great emigration to developed countries. What will occur in these countries
 which are not used to handle this relatively "old disease" will be
 definitively answered as time goes by. We will try to give some of these
 answers in the following chapters of this book.