Resurgence of Malaria Transmission and Incidence after Withdrawal of Indoor Residual Spraying in the District of Koulikoro, Mali

In Mali, malaria vector control relies mostly on long-lasting insecticidal nets and indoor residual spraying (IRS). From 2008 to 2016, an IRS program was implemented in the district of Koulikoro. After a significant reduction in malaria indicators, IRS was stopped in 2016. This study evaluated the effect of IRS withdrawal on entomological parameters of malaria transmission and incidence in children aged 6 months to 10 years in the district of Koulikoro. Entomological parameters of malaria transmission during the last year of IRS implementation in 2016 were compared with those obtained 2 years after IRS withdrawal in 2018 in two villages of Koulikoro. Mosquito vectors were collected by mouth aspiration and pyrethrum spray catches in the villages to monitor these transmission parameters. A sharp increase (10.8 times higher) in vector abundance after IRS withdrawal was observed. The infection rate of Anopheles gambiae sensu lato to Plasmodium falciparum increased from zero during IRS implementation to 14.8% after IRS withdrawal. The average entomological inoculation rate, which was undetectable before, was 1.22 infected bites per person per month 2 years after IRS was withdrawn, and the cumulative malaria incidence rate observed after IRS was 4.12 times (15.2% versus 3.7%) higher than that observed in 2016 in the villages before IRS withdrawal. This study showed a resurgence of malaria transmission and incidence in the Koulikoro health district after IRS was withdrawn. Thus, to manage the potential consequences of malaria transmission resurgence, alternative approaches are needed when stopping successful malaria control interventions.

Multiple Resistance Mechanisms to Pyrethroids Insecticides in Anopheles gambiae sensu lato Population From Mali, West Africa

Background

Insecticide-based vector control is responsible for reducing malaria mortality and morbidity. Its success depends on a better knowledge of the vector, its distribution, and resistance status to the insecticides used. In this paper, we assessed Anopheles gambiae sensu lato (A gambiae s.l.) population resistance to pyrethroids in different ecological settings.

Methods

The World Health Organization standard bioassay test was used to assess F₀A gambiae s.l. susceptibility to pyrethroids. Biochemical Synergist assays were conducted with piperonyl butoxide (PBO), S,S,S-tributyl phosphotritioate, and diethyl maleate. L1014F, L1014S, and N1575Y knockdown resistance (kdr) mutations were investigated using TaqMan genotyping.

Results

Anopheles gambiae sensu lato was composed of Anopheles arabienisis, Anopheles coluzzii, and A gambiae in all study sites. Anopheles gambiae sensu lato showed a strong phenotypic resistance to deltamethrin and permethrin in all sites (13% to 41% mortality). In many sites, pre-exposure to synergists partially improved the mortality rate suggesting the presence of detoxifying enzymes. The 3 kdr (L1014F, L1014S, and N1575Y) mutations were found, with a predominance of L1014F, in all species.

Conclusions

Multiple resistance mechanisms to pyrethroids were observed in A gambiae s.l. in Mali. The PBO provided a better partial restoration of susceptibility to pyrethroids, suggesting that the efficacy of long-lasting insecticidal nets may be improved with PBO.

Performance of pirimiphos-methyl based Indoor Residual Spraying on entomological parameters of malaria transmission in the pyrethroid resistance region of Koulikoro, Mali

Malaria vector control in Mali relies heavily on the use of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) in selected districts. As part of strengthening vector control strategies in Koulikoro district, the National Malaria Control Programme (NMCP) through the support from the US President's Malaria Initiative (PMI) has strategically driven the implementation of IRS, with the LLINs coverage also rising from 93.3% and 98.2%. Due to the increased reports of vector resistance to both pyrethroid and carbamates, there was a campaign for the use of pirimiphos-methyl, an organophosphate at Koulikoro between 2015 and 2016. In this study, the effect of IRS on malaria transmission was assessed, by comparing some key entomological indices between Koulikoro, where IRS was implemented and its neighboring district, Banamba that has never received IRS as vector control intervention. The study was conducted in two villages of each district (Koulikoro and Banamba). Pyrethrum spray catches and entry window trapping were used to collect mosquitoes on a monthly basis. WHO tube tests were carried out to assess mosquito susceptibility to insecticides. Mosquitoes were identified to species level by PCR and their infection to P. falciparum was detected by Enzyme Linked-Immuno-Sorbent Assay (ELISA). Of the 527 specimens identified, An. coluzzii was the most frequent species (95%) followed by An. gambiae (4%) and An. arabiensis (1%). Its density was rainfall dependent in the no-IRS area, and almost independent in the IRS area. The infection rate (IR) in the no-IRS area was 0.96%, while it was null in the IRS area. In the no-IRS area, the entomological inoculation rate (EIR) was 0.21 infective bites /person month with a peak in September. High resistance to pyrethroids and carbamates and susceptibility to organophosphates was observed at all sites. The introduction of pirimiphos-methyl based IRS for vector control resulted in a significant decrease in malaria transmission. An. gambiae s.l., the main malaria vector in the area, was resistant to pyrethroids and carbamates but remained susceptible to the organophosphate pirimiphos-methyl.

Indoor and outdoor malaria transmission in two ecological settings in rural Mali: implications for vector control

Background

Implementation and upscale of effective malaria vector control strategies necessitates understanding the multi-factorial aspects of transmission patterns. The primary aims of this study are to determine the vector composition, biting rates, trophic preference, and the overall importance of distinguishing outdoor versus indoor malaria transmission through a study at two communities in rural Mali.

Methods

Mosquito collection was carried out between July 2012 and June 2016 at two rural Mali communities (Dangassa and Koïla Bamanan) using pyrethrum spray-catch and human landing catch approaches at both indoor and outdoor locations. Species of Anopheles gambiae complex were identified by polymerase chain reaction (PCR). Enzyme-Linked -Immuno-Sorbent Assay (ELISA) were used to determine the origin of mosquito blood meals and presence of Plasmodium falciparum sporozoite infections.

Results

A total of 11,237 An. gambiae sensu lato (s.l.) were collected during the study period (5239 and 5998 from the Dangassa and Koïla Bamanan sites, respectively). Of the 679 identified by PCR in Dangassa, Anopheles coluzzii was the predominant species with 91.4% of the catch followed by An. gambiae (8.0%) and Anopheles arabiensis (0.6%). At the same time in Koïla Bamanan, of the 623 An. gambiae s.l., An. coluzzii accounted for 99% of the catch, An. arabiensis 0.8% and An. gambiae 0.2%. Human Blood Index (HBI) measures were significantly higher in Dangassa (79.4%; 95% Bayesian credible interval (BCI) [77.4, 81.4]) than in Koïla Bamanan (15.9%; 95% BCI [14.7, 17.1]). The human biting rates were higher during the second half of the night at both sites. In Dangassa, the sporozoite rate was comparable between outdoor and indoor mosquito collections. For outdoor collections, the sporozoite positive rate was 3.6% (95% BCI [2.1–4.3]) and indoor collections were 3.1% (95% BCI [2.4–5.0]). In Koïla Bamanan, the sporozoite rate was higher indoors at 4.3% (95% BCI [2.7–6.3]) compared with outdoors at 2.4% (95% BCI [1.1–4.2]). In Dangassa, corrected entomological inoculation rates (cEIRs) using HBI were 13.74 [95% BCI 9.21–19.14] infective bites/person/month (ib/p/m) at indoor, and 18.66 [95% BCI 12.55–25.81] ib/p/m at outdoor. For Koïla Bamanan, cEIRs were 1.57 [95% BCI 2.34–2.72] ib/p/m and 0.94 [95% BCI 0.43–1.64] ib/p/m for indoor and outdoor, respectively. EIRs were significantly higher at the Dangassa site than the Koïla Bamanan site.

Conclusion

The findings in this work may indicate the occurrence of active, outdoor residual malaria transmission is comparable to indoor transmission in some geographic settings. The high outdoor transmission patterns observed here highlight the need for additional strategies to combat outdoor malaria transmission to complement traditional indoor preventive approaches such as long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) which typically focus on resting mosquitoes.

Performance of IRS on malaria prevalence and incidence using pirimiphos-methyl in the context of pyrethroid resistance in Koulikoro region, Mali

Background

Koulikoro Health District is one of three districts of Mali where the indoor residual spray (IRS) has been implemented from 2008 to 2016. With widespread of resistance to pyrethroid, IRS was shifted from pyrethroid to pirimiphos-methyl from 2014 to 2016. The objective of this study was to assess the added value of IRS to LLINs on the prevalence of parasitaemia and malaria incidence among children under 10 years old.

Methods

A comparative study was carried out to assess the effects of pirimiphos-methyl based IRS on malaria prevalence and incidence among children from 6 months to 10 years old in selected pyrethroid resistance villages of two health districts in Mali: one where IRS was implemented in combination with LLINs (intervention area) and one with LLINs-only (control area). Two cross-sectional surveys were carried out at the beginning (June) and end of the rainy season (October) to assess seasonal changes in malaria parasitaemia by microscopy. A passive detection case (PCD) was set-up in each study village for 9 months to estimate the incidence of malaria using RDT.

Results

There was an increase of 220% in malaria prevalence from June to October in the control area (14% to 42%) versus only 53% in the IRS area (9.2% to 13.2%). Thus, the proportional rise in malaria prevalence from the dry to the rainy season in 2016 was 4-times greater in the control area compared to the IRS area. The overall malaria incidence rate was 2.7 per 100 person-months in the IRS area compared with 6.8 per 100 person-month in the control areas. The Log-rank test of Kaplan–Meier survival analysis showed that children living in IRS area remain much longer free from malaria (Hazard ratio (HR) = 0.45, CI 95% 0.37–0.54) than children of the control area (P < 0.0001).

Conclusions

IRS using pirimiphos-methyl has been successful in reducing substantially both the prevalence and the incidence of malaria in children under 10 years old in the area of pyrethroid resistance of Koulikoro, Mali. Pirimiphos-methyl is a better alternative than pyrethroids for IRS in areas with widespread of pyrethroid resistance.

Acetylcholinesterase (ace-1R) target site mutation G119S and resistance to carbamates in Anopheles gambiae (sensu lato) populations from Mali

BACKGROUND

The long-lasting insecticidal nets (LLINs) and indoor residual spraying of insecticide (IRS) are major malaria vector control strategies in Mali. The success of control strategies depends on a better understanding of the status of malaria vectors with respect to the insecticides used. In this study we evaluate the level of resistance of Anopheles gambiae (sensu lato) to bendiocarb and the molecular mechanism that underlies it.

METHODS

Larvae of An. gambiae (s.l.) were collected from breeding habitats encountered in the three study sites and bioassayed with bendiocarb. The ace-1 target site substitution G119S was genotyped using a TaqMan assay.

RESULTS

The three species of the An. gambiae complex in Mali, i.e. An. arabiensis, An. coluzzii and An. gambiae (s.s.) were found in sympatry in the three surveyed localities with different frequencies. We observed a resistance and suspicious resistance of the three species to bendiocarb with a mortality rate ranging from 37% to 86%. The allelic frequency of the G119S mutation was higher in An. gambiae (s.s.) compared to the other two species; 42.86%, 25.61% and 16.67% respectively in Dangassa, Koula, and Karadié. The allelic frequency of G119S in An. coluzzii ranged from 4.5% to 8.33% and from 1.43% to 21.15% for An. arabiensis. After exposure to bendiocarb, the G119S mutation was found only in survivors. The survival of Anopheles gambiae (s.l) populations from the three surveyed localities was associated with the presence of the mutation.

CONCLUSIONS

The study highlights the implication of G119S mutation in bendiocarb resistance in An. gambiae (s.s.), An. arabiensis and An. coluzzii populations from the three surveyed localities.

[Susceptibility status of Anopheles gambiae sensu lato to insecticides commonly used for malaria control in Mali]

The objective of this work was to monitor the susceptibility of malaria vectors to insecticides in nine sentinel sites of the National Malaria Control Program in Mali. The study was performed during the rainy seasons of 2010 and 2011. WHO bioassays were conducted using F0 and/or F1 from wild collected females. The insecticides used were lambda-cyhalothrin 0.05%, DDT 4%, permethrin 0.75%, deltamethrin 0.05%, bendiocarb 0.1% and fenitrothion 1.0%. Results showed suspicion of resistance to pyrethroids and organochlorine in An. gambiae s.l. at almost all the sites except Yanfolila where the vector was susceptible to lambda-cyhalothrin (98.0%) [CI 95%, 98-99.8] and to DDT (100%). An. gambiae s.l. was susceptible to bendiocarb in five of the sites (Gao, Bougouni, Djenné, Yanfolila, Tombouctou) while there was a suspicion of resistance at the other sites (Kati, Niono, Bandiagara, Kita). Fenitrothion remains efficient except in the rice area of Niono, where there was a suspicion of resistance with a mortality rate of 92% [IC 95% 88.3-94.8]. Thus, it could be used as an alternative insecticide for IRS in Mali. These results show resistance to pyrethroids, the main insecticide family used in public health (and to some extent in agriculture). This could compromise the malaria vector control efforts in Mali where pyrethroids are used for both in bed nets and in IRS.

[Epidemiology and maternal prognosis of eclampsia in the intensive care unit at the University Hospital of Point G, Bamako]

OBJECTIVE

This research aimed to analyze the epidemio- clinical characteristic and the prognosis of patients with eclampsia admitted to the intensive care unit at the University Hospital of Point G.

MATERIALS AND METHODS

The clinical records of all patients admitted to intensive care for eclampsia from September 2009 to February 2011 were retrospectively collected. We analyzed the following parameters: age, parity, gravidity, the admission deadline, the beginning of eclampsia compared to the term of pregnancy, the number of seizure, mode of delivery, score of Glasgow, blood pressure, proteinuria, complications and evolution.

RESULTS

Among 702 admissions, 158 patients, with a mean age of 20 ± 4 were hospitalized for eclampsia (22.5%). We recorded 106 cases of first pregnancies (67.1%) and 104 primiparous (65.8%). The admission period after the first seizure was over 6 hours for 90 patients (57%). The first seizure had occurred in ante-partum period for 69 patients, in per-partum period for 4 patients and in postpartum period for 85 patients.

Ninety-three patients (59%) had consciousness disorders at admission, 12 patients received oxygen treatment .Vaginal delivery was the mode of delivery for 93 patients and cesarean section for 65 patients.Eclampsia was associated with renal failure in 25 patients, HELLP syndrome for 15 patients, the stroke for 5 patients, acute pulmonary edema for 3 patients, the coagulation disorders for one patient; and the sepsis for 6 patients. Maternal and perinatal lethality was 9.5% and 10.8% respectively.

CONCLUSION

Eclampsia is a frequent medical and obstetric emergency in intensive care unit of the University Hospital of Point G and affects young patients during their first pregnancy and delivery. Maternal and perinatal lethality remains high, due to the delay in the cases management and the associated factors of gravity. Strong actions are needed to raise awareness for early medical visit and to prepare medical teams for better cases management.

[Intestinal invagination occurring during pregnancy: 1 case]

Acute intestinal invagination is a rare pathology in adults; even more so on specific fields as in pregnant women. Therapeutic indications depend on the duration of the invagination. We noted a cases of acute intestinal invagination after 72 hours of evolution in a multiparous 35 year old woman, 27 weeks pregnant, successfully treated by surgery and tocolysis.

[Role Of Emigration In The Spread Of HIV Infection In The Region Of Kayes, Mali]

AIM

To determine the impact of emigration on HIV transmission in the Kayes region.

PATIENTS AND METHODS

It was a cross-sectional study conducted in 2007 in the Fousseyni DAOU Hospital of Kayes. A total of 109 subjects were included - all participants were over 14 years old and were diagnosed as HIV positive. The variables studied were knowledge, attitudes and behaviors regarding HIV/AIDS, the notion of traveling outside of Mali and emigration. Pearson Chi² and Fisher test were used for a bivariate analysis.

RESULTS

The female/male sex ratio was of 2.51. In this data pool, 32.3% (10/31) of men were emigrants. More than a third 37.2% (29/78) of women had an emigrant as a sexual partner. There was no significant difference in the levels of knowledge regarding HIV between emigrants and those who never went abroad. The likelihood of having had relations with a sex worker in the preceding 12 months was nine times higher for an emigrant than to a non-emigrant [OR=9.13, CI 95% (2.20 - 37.84)].

An emigrant was five times more likely to have at least two sexual partners [OR=5.11, CI 95% (1.37-18.94)].

CONCLUSION

This study showed that emigration is an important factor regarding the spread of HIV in the region of Kayes Mali. Sensitization of the candidates to emigration must be reinforced.

Absence of dry season Plasmodium parasitaemia, but high rates of reported acute respiratory infection and diarrhoea in preschool-aged children in Kaédi, southern Mauritania

Background

The epidemiology of malaria in the Senegal River Gorgol valley, southern Mauritania, requires particular attention in the face of ongoing and predicted environmental and climate changes. While “malaria cases” are reported in health facilities throughout the year, past and current climatic and ecological conditions do not favour transmission in the dry season (lack of rainfall and very high temperatures). Moreover, entomological investigations in neighbouring regions point to an absence of malaria transmission in mosquito vectors in the dry season. Because the clinical signs of malaria are non-specific and overlap with those of other diseases (e.g. acute respiratory infections and diarrhoea), new research is needed to better understand malaria transmission patterns in this region to improve adaptive, preventive and curative measures.

Methods

We conducted a multipurpose cross-sectional survey in the city of Kaédi in April 2011 (dry season), assessing three major disease patterns, including malaria. Plasmodium spp. parasite rates were tested among children aged 6–59 months who were recruited from a random selection of households using a rapid diagnostic test and microscopic examination of Giemsa-stained thick and thin blood films. Acute respiratory infection and diarrhoea were the two other diseases investigated, administering a parental questionnaire to determine the reported prevalence among participating children.

Findings

No Plasmodium infection was found in any of the 371 surveyed preschool-aged children using two different diagnostic methods. Acute respiratory infections and diarrhoea were reported in 43.4% and 35.0% of the participants, respectively. About two thirds of the children with acute respiratory infections and diarrhoea required medical follow-up by a health worker.

Conclusions

Malaria was absent in the present dry season survey in the capital of the Gorgol valley of Mauritania, while acute respiratory infections and diarrhea were highly prevalent. Surveys should be repeated towards the end of rainy season, which will enhance our understanding of the potential changes in malaria transmission in a region known as ‘hot spot’ of predicted climate change.

[Community-based intervention to reduce birth asphyxia mortality in Mali]

Approximately one million newborn babies die every year as a result of birth asphyxia in developing countries. The objectives of this study are to develop the management of birth asphyxia and to establish a community-based surveillance system of vital events in rural areas of Oueléssébougou, Mali. Traditional birth attendants, female leaders of village associations and village health workers were trained to carry out communication activities designed to change behaviours in the management of birth asphyxia. The study has improved health facility-based delivery (from 80 to 93%) and the identification of birth asphyxia (11 to 12% new born babies have been resuscitated). As a result of training and supervising community actors, the quality of delivery is improved and neonatal mortality is reduced.

[Medical care of post-operative pain in pediatric surgery: comparison of three protocols]

The gains of the struggle against the pain of the child are still fragile and poorly insured despite advances in both information and evaluate the degree of pain in the range of means at our disposal. The absence of systematic management of pain especially post-operative pain in pediatric surgery and the difficulty of obtaining a vein justify this study.

PURPOSE

The purpose was to compare analgesic effect of three protocols.

TYPE OF STUDY

prospective and comparative study.

MATERIAL AND METHOD

Our study was prospective and comparative. It took place in the services of anesthesia and intensive care and pediatric surgery of Gabriel Toure Hospital in Bamako during October 2003 to July 2004.Patients were randomized to three protocols: protocol A patients who received paracetamol suppository at a dose of 15 mg/kg,protocol B patients who received niflumique acid suppository at a dose of 13 mg/kg and protocol C patients who receiving combination paracetamol at a dose of 15 mg/kg with acid niflumique at a dose of 13 mg/kg per rectally. The first dose for each protocol was administered after anesthetic induction. In Protocol C paracetamol was administered immediately after induction and niflumique acid on awakening.

RESULTS

During the period, 202 patients were randomized to three protocols: protocol A (n = 65), protocol B (n = 69),protocol C (n = 68). Poignant pain has been observed with EVS ladder against none with the grid OPS.Patients of protocol C surgery for hernia had moderate pain with 4.40% of cases against 9.60% of patients in the protocol B with P = 0.0024 and 12% of patients in Protocol A, with P = 0.0018 in OPS. Patient's protocol C surgery for hernia showed no intensive pain against 14.20% of the patients in protocol B and 11.4% of patients in group A with EVS scale. No side effects related molecules have been observed in the three protocols.

CONCLUSION

Association of paracetamol and niflumique acid provides a quality analgesia by postoperative rectally in pediatric surgery.

[Tinea capitis in department of dermatology and venerology in the University hospital of Donka at Conakry, Guinea]

The authors report the results of a study carried out on tinea capitis, in the Department of Dermatology and Venerology at the University Hospital of Donka in Conakry, during one year In this department, the tinea capitis represents 3.2% of the consultations and remains the second mycosis. Out of 414 consulted children, a male predominance of 75% was noted especially regarding the Trichophytic tinea. School children aged of 6-14 years old are the most affected by the disease. The trichophytic tinea is widely spread with 65.5% more than the microsporic 17% and inflammatory tinea 16.5%. The mixed tinea is exceptional and no case of favus has been found. The Trichophyton violaceum is the most dermatophyte to be found 56.70% whereas a survey carried out in 1959 showed the predominance of T. soudanense and M. audouini. The Microsporum canis and an association of M. canis and T. violaceum are also to be found.