Results of this study show that refusers of IRS in Tanzania tend to be more knowledgeable people such as teachers, drivers, extension workers, and other civil servants who do not simply follow the orders of the local government or the sprayers, but are skeptical about the process until they see true results. It seems as if community members have a basic understanding of IRS, however, it will take more in-depth education of the more skeptical members to decrease the refusal rate. Refusal took three forms: 1) refusing partially until thorough explanation is provided; 2) accepting spray to be done in a few rooms only; and 3) refusing outright. There were very few cases of total refusal in which people vehemently admitted refusing the spray. In most of the refusal interviews, participants justified why their houses were not sprayed, often without admitting that they had refused. Reasons for refusal included initial ignorance about the reasons for IRS, uncertainty about its effectiveness, increased prevalence of other insects, potential physical side effects, odour, rumours about the chemical affecting fertility, embarrassment about moving poor quality possessions out of the house to be seen by neighbours, logistical difficulties, and belief that the spray was politically motivated.
The results of the current research, while specific to communities in Tanzania, produced some themes that are highly consistent with previous findings in other countries.
Logisitics of IRS implementation
Logistically, local recruitment of sprayers  given proper training and education, financial incentives for sprayers in terms of salary or honorariums, good working partnerships with local health officials, and community education and mobilization all appear to contribute to acceptability of IRS [12–14]. One of the factors leading to successful eradication of malaria in Taiwan in the 1960s is said to be the carefully delivered health messages and information that were disseminated before spraying was undertaken . Community members were given incentives for reporting malaria cases and their efforts, and photographs were published in local newsletters . Reports of IRS interventions by the MENTOR Initiative in crisis-affected areas in Kenya, Chad, and Central African Republic demonstrate how sprayers were locally recruited and trained in spraying and disseminating health messages. Further, the community received an explanation of the benefits of spraying before it began [12–14]. This likely played an important role in achieving very high rates of spraying coverage that often exceeded the set targets. Many of these same facilitators and barriers to successful implementation also appeared in the current study. Taken in conjunction with findings from other countries, perhaps a stronger focus on logistics and uniform training and education could further increase acceptance rates in Tanzania.
Lack of information on why spraying is done has been reported both as a potential problem  and a barrier to IRS acceptance [17, 18], and this study is consistent with this repeated finding. Sprayers often arrive without forewarning and have little ability to give information on why spraying is being done and the benefits of spraying [19–21]. In a study by Montgomery et al., people did not understand why IRS was conducted but accepted it. Other studies have found that many respondents object to spraying since they do not understand how it works [17, 18]. Many households believe that spraying is not effective in preventing malaria . Some believe that while prior rounds were useful, subsequent rounds of spraying were futile . Others believe that the insecticide solution is too diluted to be effective . These are all consistent with findings in the current research.
This study showed that a minority of participants did not appreciate the work of the sprayers themselves, sometimes believing they had diluted the chemical, had gotten the job without being well qualified, or were not knowledgeable enough to be implementing such an important activity. Other studies have also shown the conduct of sprayers to be questionable. This was observed in a study in Thailand, which detailed how sprayers stole household possessions; spray team leaders tried to sell anti-malarial medicines while on spraying rounds; did not object to incorrect dilution of DDT by sprayers; and behaved rudely towards villagers . A previous study in Dar es Salaam and Tanga Tanzania found that some respondents complained sprayers avoided spraying in houses that were not located on main roads . While respondents in a study in one province of South Africa were largely satisfied with the conduct of sprayers, some complained that sprayers left a mess and damaged household items . In other studies, it has been reported that there was also a fear that sprayers may make known publicly the value of one’s household goods , a fear that was expressed in this study. While dissatisfaction with sprayers in the current study was rare, it usually revolved around suspicion of over diluting the chemical or the sprayers not being sufficiently knowledgeable about IRS.
The issue for women regarding IRS in the current study involved logistics of moving possessions out of the home (which could be heavy) while at the same time caring for children. This is slightly different from gender-related challenges in other studies. For instance, in a review of the impact of vector control on women, it was found that the entry of other males into domestic space during times when men of the household are away may be objectionable to some . In that study, when young boys were sent as spray personnel, they were allowed into homes. However, when an adult male sprayer was sent, he was denied entry. The participants in the current study expressed no preference for gender of the sprayers, only the logistics of preparing for the spray was of concern for women.
There was some inconsistency in the belief that IRS actually kills insects in the current study, as some participants reported seeing fewer after a round of spraying, while others saw an increase in certain critters. Other research has shown related inconsistencies. A study in Chiapas, Mexico found that 83.7% of respondents perceived that spraying was beneficial in reducing mosquito bites and cockroaches . However, community resistance on account of a perceived increase in bedbug and/or cockroach population or the activity of such insects has been repeatedly reported [18, 20, 22]. In Surinam, the increased number of cockroaches started attacking crops and biting children . Rafatjah  reported that the chemicals used in IRS may make bedbugs irritable and increase their mobility, giving the false impression that infestation has increased. Further, over time bed bugs may become resistant to the chemicals and reappear. Residents might object to spraying if they think that spraying is a cause of the bed bug problem . A study on the size and life stage structures of heavy infestations of bed bugs in Zulu huts in South Africa also reported that people whitewash walls after DDT spraying since it is perceived to increase biting by bed bugs . A review of malaria control in India has noted that householders are “definitely suffering from high populations of bed bugs resistant to DDT and BHC” . This confusion as to why some bugs appear after spraying found in studies in other countries is consistent with the current research. Perhaps making community members more aware of the types of insects that may become more visible after spraying (and why) would eliminate beliefs that the spray is ineffective at reducing malaria-carrying mosquitoes.
Unlike Tanzania, objection to IRS activities in other parts of the world could be related to the use of DDT, a synthetic pesticide that, while highly effective, is controversial because of its potential negative impacts on agriculture and the environment. The odour of DDT has also been reported to be objectionable [13, 19, 21]. While there were no claims that ICON used in Tanzania affected agriculture or the environment (participants only heard rumours of this), odour was an issue that arose occasionally in the interviews.
IRS and politics
Some studies have found that acceptability may not always be related to perceived effectiveness of spraying at all and is instead linked with deference to government authorities or politics. A study in Mozambique found that IRS was generally acceptable and generated a positive response from both householders and health care professionals. The respondents, however, did not perceive IRS to be effective against mosquitoes and believed that the effects were short-lived or non-existent. Rather, acceptance was based on a sense of patriotism, citizenship, a belief in good intentions of local politicians and leaders, and perceived obligation to accept government initiatives that were meant for the good of the people . Some expressed that refusing spraying would amount to ingratitude. Respondents thus opined that they were in favour of more spraying. An observational study in Thailand had similar findings such that the poor generally accepted spraying since they felt obligated to comply with sprayers, who they thought were government officials, while people of higher socio-economic status were more likely to resist spraying . This is highly consistent with the current study, where many participants expressed fear that there would be negative retribution by authorities if they did not comply with the spray process.
Political motivations, or the perception of such, was a recurring theme in the current study. This was also shown to be a concern among Maroons in Surinam, where resistance to sparying was associated with intra-clan rivalry, and distrust was prevalent when sprayers were from a different clan and perceived to be more well-off . In some places, sprayers were recruited exclusively on the basis of clan or religion. Barnes and Jenkins  noted that by resisting spraying, householders sought to reduce the salary that would be earned by the sprayers who were not from their clan. Not seeking blessings from local chiefs before initiating spraying was also perceived as a sign of disrespect. The political issues related to spraying in Tanzania seem to be more focused on the belief that political parties are sponsoring the spraying in order to win votes, which could have been exacerbated by the fact that some of the regions in which this research took place were receiving their first round of spraying around the 2010 national election.
It seems as though rejection of IRS, while rare, could be addressed by focusing more on strategic community mobilization and education. With more awareness as to the barriers that exist to acceptance of IRS as outlined in this study, those obstacles could be easily overcome with targeted informational and educational communication.
Recommendations for moving forward with IRS
The primary recommendation for improving IRS uptake is more comprehensive education of the communities. RTI International subcontracted NGOs and community based organizations (CBOs) to implement IEC activities in the districts. The government played a major role in the selection of NGOs/CBOs in collaboration with RTI and also provided supportive supervision and guidance to them. The NGOs were given funds by RTI to conduct all IEC trainings and advocacy meetings from the district down to the hamlet level. Community leaders (local government) worked hand in hand with NGOs/CBOs to make sure they reached community members with correct information about IRS and malaria in general. But with all of these players involved, it is possible that a more streamlined education process to the communities would be more effective. Perhaps general information meetings could be held focused entriely on IRS, and IEC materials could be distributed, but then NGOs could host follow up meetings to answer additional questions from those who are still skeptical or want more information. The data from this study show that refusal of IRS is usually not just a matter of community members being disagreeable, but rather a misunderstanding or lack of understanding of the process and long-term effects of the exercise. It seems as if a follow-up to initial educational sessions or materials as needed would ensure greater acceptance.
There should also be a focus on encouraging community leaders to educate their constituents rather than threaten them with punishments for noncompliance. Improper involvement of local governmental leaders in community mobilization in IRS appears to have led many to accept spraying not voluntarily, but as part of their civic duty, which mirror findings from studies in Mozambique and Thailand [16, 20]. As a result, people’s compliance with IRS should not be equated with people’s acceptance of IRS. Threats by community leaders may have contributed greatly to the reported IRS acceptance. The implications of this passive as opposed to voluntary compliance may in the future encourage people to circumvent the spray process so as to satisfy the community leaders’ demands, either by lying about whether their homes have been sprayed or purposely fleeing the area during spraying days so as to make their homes unavailable. The data from the current study already show these tactics are taking place.
Also important to note is that NGOs utilize different strategies to mobilize communities on IRS acceptance. If these strategies were standardized to some extent (e.g., NGOs had to hold a certain number of community meetings and cover a prescribed agenda) and engaged more closely and appropriately with local authorities, refusal rates may decrease.
Finally, given the changing malaria situation in the country due to IRS, continued efforts are needed to emphasize the benefits of maintaining concurrent use of multiple methods of preventing malaria through community health promotion. A separate study to investigate how nets are being used in homes, whether they are used consistently in sprayed homes, who uses which nets (old or new), and how old nets are disposed of, as all of these factors relate to the introduction of IRS, would contribute to improving coordination of malaria prevention programmes in Tanzania.
Being of qualitative design, this study did not seek to generalize findings to the districts/regions or social/cultural groups that participated in the study. Instead, it aimed to provide highlights on the contextual issues that may have a bearing on the acceptance or rejection of IRS in Tanzania.
Another limitation in this study was the definition of concepts: acceptor and refuser. There was no clear dividing line between the acceptor and refuser, and “refusal” quickly became a gray area. Very few individuals declared themselves “refusers”. A majority of people who refused IRS (as indicated by the red sticker on their doorsteps and confirmed by community leaders) did not classify themselves in that way, and this affected the mode of asking questions. As a solution to this, the questions to a refuser in an interview were often posed by referring to the third person (i.e., seeking views or opinions of the interviewee about refusers in his/her community instead of asking for one’s personal opinion). For instance, of all the refusers interviewed, none answered a direct yes to the question, “Did you refuse to have your house sprayed?” Refusers tended to be highly suspicious of the research team, sometimes equating them with a government mission to follow up on IRS refusers. This mistrust between the study team and the community leaders on the one hand and refusers on the other hand indicates a lack of intensive community mobilization.
Interpretation of findings on IRS in Zanzibar deserves special attention. With its low malaria incidence and shift to targeted spraying, Zanzibar experiences specific needs and strategies so as to maintain acceptance of IRS. Findings indicate that formerly, IRS acceptance and rejection were divided politically in Zanzibar. Now that the country underwent referendum in 2010, political differences were not among the reasons for refusal of IRS. In fact, views from community and NGO leaders interviewed in the current study indicate that IRS refusals in Zanzibar are fewer than ever before, despite the shift from blanket spraying to targeted spraying. Important also to note is how Zanzibar has shifted away from treating malaria interventions (e.g., case management, malaria in pregnancy, vector control and community mobilization) as disconnected efforts. In the Zanzibar data from this study, it was evident that community members stress the importance of these interventions simultaneously and sometimes concurrently. It can therefore be tentatively concluded that as the level of malaria transmission decreases, emphasis on implementing several interventions concurrently becomes imperative.
Timing of data collection may also have influenced results. A majority of the data was collected at the beginning of the rainy season before prevalence of mosquitoes visibly increased. As the rainy season progressed, it is possible that benefits of IRS were seen more clearly by communities. Data collection also began around the 2010 National Election. The research team was sometimes unknowingly associated with political parties rather than independent evaluators of IRS, which may have influenced participants’ willingness to be honest about their experiences with the spraying process.